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1. Numerical schemes for the aggregation equation with pointy potentials

Author: François Delarue, Sofiane Martel, Frédéric Lagoutière, Kévin Le Balc'h, Hélène Hivert, Nicolas Vauchelet, Benoît Fabrèges, Institut Camille Jordan [Villeurbanne] (ICJ), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Modélisation mathématique, calcul scientifique (MMCS), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Institut de Recherche Mathématique de Rennes (IRMAR), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire Jean Alexandre Dieudonné (JAD), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Analyse, Géométrie et Applications (LAGA), Université Paris 8 Vincennes-Saint-Denis (UP8)-Centre National de la Recherche Scientifique (CNRS)-Institut Galilée-Université Paris 13 (UP13), Institut Camille Jordan [Villeurbanne] ( ICJ ), École Centrale de Lyon ( ECL ), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Institut National des Sciences Appliquées de Lyon ( INSA Lyon ), Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Université Jean Monnet [Saint-Étienne] ( UJM ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Recherche Mathématique de Rennes ( IRMAR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -AGROCAMPUS OUEST-École normale supérieure - Rennes ( ENS Rennes ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -Institut National des Sciences Appliquées ( INSA ) -Université de Rennes 2 ( UR2 ), Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement ( Cerema ) -EDF R&D ( EDF R&D ), EDF ( EDF ) -EDF ( EDF ), Laboratoire Jean Alexandre Dieudonné ( JAD ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Analyse, Géométrie et Applications ( LAGA ), Université Paris 8 Vincennes-Saint-Denis ( UP8 ) -Université Paris 13 ( UP13 ) -Université Sorbonne Paris Cité ( USPC ) -Institut Galilée-Centre National de la Recherche Scientifique ( CNRS ), Institut Camille Jordan (ICJ), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), Laboratoire Jean Alexandre Dieudonné (LJAD), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris 13 (UP13)-Institut Galilée-Centre National de la Recherche Scientifique (CNRS), and ANR-11-LABX-0020,LEBESGUE,Centre de Mathématiques Henri Lebesgue : fondements, interactions, applications et Formation(2011)
Subjects: T57-57.97, Finite volume method, Applied mathematics. Quantitative methods, Collective motion, 02 engineering and technology, 01 natural sciences, Measure (mathematics), Nonlinear conservation law, 010101 applied mathematics, [ MATH.MATH-AP ] Mathematics [math]/Analysis of PDEs [math.AP], Convergence (routing), 0202 electrical engineering, electronic engineering, information engineering, QA1-939, Applied mathematics, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], 020201 artificial intelligence & image processing, 0101 mathematics, Finite time, Focus (optics), Mathematics
Abstract: International audience; The aggregation equation is a nonlocal and nonlinear conservation law commonly used to describe the collective motion of individuals interacting together. When interacting potentials are pointy, it is now well established that solutions may blow up in finite time but global in time weak measure valued solutions exist. In this paper we focus on the convergence of particle schemes and finite volume schemes towards these weak measure valued solutions of the aggregation equation.
Published: 2019
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2. Towards a new friction model for shallow water equations through an interactive viscous layer

Author: Hoang-Minh Le, François James, Mathilde Legrand, Pierre-Yves Lagrée, Institut Denis Poisson (IDP), Centre National de la Recherche Scientifique (CNRS)-Université de Tours (UT)-Université d'Orléans (UO), Institut Jean Le Rond d'Alembert (DALEMBERT), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Centre National de la Recherche Scientifique (CNRS)-Université de Tours-Université d'Orléans (UO), Institut Denis Poisson ( IDP ), Université de Tours-Centre National de la Recherche Scientifique ( CNRS ) -Université d'Orléans ( UO ), Institut Jean Le Rond d'Alembert ( DALEMBERT ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement ( Cerema ) -EDF R&D ( EDF R&D ), and EDF ( EDF ) -EDF ( EDF )
Subjects: 76N17, friction law, 010504 meteorology & atmospheric sciences, von Kármán equation, Hydrostatic pressure, Perfect fluid, Föppl–von Kármán equations, 01 natural sciences, 65M08, 010305 fluids & plasmas, Physics::Fluid Dynamics, Superposition principle, Mathematics - Analysis of PDEs, [ MATH.MATH-AP ] Mathematics [math]/Analysis of PDEs [math.AP], viscous layer, 0103 physical sciences, 35L65, FOS: Mathematics, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Prandtl equation, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Shallow water equations, 2010 AMS subject classifications: Primary: 35L60, 35Q35, 0105 earth and related environmental sciences, Mathematics, von Kármán equation 2010 AMS subject classifications: 35L60, Numerical Analysis, Finite volume method, Applied Mathematics, [ PHYS.MECA.MEFL ] Physics [physics]/Mechanics [physics]/Mechanics of the fluids [physics.class-ph], shallow water, Mechanics, Computational Mathematics, Boundary layer, Waves and shallow water, Modeling and Simulation, Analysis, Analysis of PDEs (math.AP)
Abstract: The derivation of shallow water models from Navier–Stokes equations is revisited yielding a class of two-layer shallow water models. An improved velocity profile is proposed, based on the superposition of an inviscid fluid and a viscous layer inspired by the Interactive Boundary Layer interaction used in aeronautics. This leads to a new friction law which depends not only on velocity and depth but also on the variations of velocity and thickness of the viscous layer. The resulting system is an extended shallow water model consisting of three depth-integrated equations: the first two are mass and momentum conservation in which a slight correction on hydrostatic pressure has been made; the third one, known as von Kármán equation, describes the evolution of the viscous layer. This coupled model is shown to be conditionally hyperbolic, and a Godunov-type finite volume scheme is also proposed. Several numerical examples are provided and compared to the Multi-Layer Saint-Venant model. They emphasize the ability of the model to deal with unsteady viscous effects. They illustrate also the phase-lag between friction and topography, and even recover possible reverse flows.
Published: 2019
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3. Improving simulations of extreme skew surges through waves' contributions

Author: Lalanne, Cécile, Frau, Roberto, Andreevsky, Marc, Pham, Chi-Tuan, Raoult, Cécile, Laborie, Vanessya, Giloy, Nathalie, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), Centre d'Etudes et d'Expertises sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet HA (Cerema Equipe-projet HA), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), and Institut de Radioprotection et de Sûreté Nucléaire (IRSN)
Subjects: hindcast, [SDE.IE]Environmental Sciences/Environmental Engineering, Skew surges, Telemac2D, Charnock coefficient, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience
Published: 2018

4. Reduced basis approximation and a posteriori error bounds for 4D-Var data assimilation

Author: Mark Kärcher, Sébastien Boyaval, Karen Veroy, Martin A. Grepl, Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), MATHematics for MatERIALS (MATHERIALS), Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS), École des Ponts ParisTech (ENPC)-École des Ponts ParisTech (ENPC)-Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Rheinisch-Westfälische Technische Hochschule Aachen ( RWTH ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement ( Cerema ) -EDF R&D ( EDF R&D ), EDF ( EDF ) -EDF ( EDF ), MATHematics for MatERIALS ( MATHERIALS ), Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique ( CERMICS ), École des Ponts ParisTech ( ENPC ) -École des Ponts ParisTech ( ENPC ) -Inria de Paris, Institut National de Recherche en Informatique et en Automatique ( Inria ) -Institut National de Recherche en Informatique et en Automatique ( Inria ), Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS), and École des Ponts ParisTech (ENPC)-École des Ponts ParisTech (ENPC)
Subjects: Reduced-order models, Control and Optimization, Optimization problem, 010504 meteorology & atmospheric sciences, Aerospace Engineering, Weak-constraint, 010103 numerical & computational mathematics, 01 natural sciences, Strong-constraint, Data assimilation, FOS: Mathematics, Parameter estimation, Initial value problem, Applied mathematics, Variational data assimilation, 0101 mathematics, Electrical and Electronic Engineering, Mathematics - Optimization and Control, 0105 earth and related environmental sciences, Civil and Structural Engineering, Mathematics, 65K10, Basis (linear algebra), Estimation theory, Mechanical Engineering, Function (mathematics), [ MATH.MATH-NA ] Mathematics [math]/Numerical Analysis [math.NA], A posteriori error estimation, Optimization and Control (math.OC), 4D-Var, A priori and a posteriori, Errors-in-variables models, PDE-constrained optimization, Reduced basis method, Software, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA]
Abstract: International audience; We propose a certified reduced basis approach for the strong-and weak-constraint four-dimensional variational (4D-Var) data assimilation problem for a parametrized PDE model. While the standard strong-constraint 4D-Var approach uses the given observational data to estimate only the unknown initial condition of the model, the weak-constraint 4D-Var formulation additionally provides an estimate for the model error and thus can deal with imperfect models. Since the model error is a distributed function in both space and time, the 4D-Var formulation leads to a large-scale optimization problem for every given parameter instance of the PDE model. To solve the problem efficiently, various reduced order approaches have therefore been proposed in the recent past. Here, we employ the reduced basis method to generate reduced order approximations for the state, adjoint, initial condition, and model error. Our main contribution is the development of efficiently computable a posteriori upper bounds for the error of the reduced basis approximation with respect to the underlying high-dimensional 4D-Var problem. Numerical results are conducted to test the validity of our approach.
Published: 2018
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5. La base de données TEMPETES : un support pour une expertise collégiale et interdisciplinaire des informations historiques de tempêtes et de submersions

Author: Roberto Frau, Franck Mazas, Thierry Sauzeau, Nathalie Giloy, Thomas Bulteau, Yann Ferret, Claire-Marie Duluc, LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Morphodynamique Continentale et Côtière (M2C), Centre National de la Recherche Scientifique (CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Centre de Recherche Interdisciplinaires en Histoire, Histoire de l'Art et Musicologie (CRIHAM), Université de Poitiers-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université de Poitiers
Subjects: 021110 strategic, defence & security studies, 010504 meteorology & atmospheric sciences, Surcotes, [SHS.ENVIR]Humanities and Social Sciences/Environmental studies, Base de données, Niveaux marins 823 Thème 7 -Risques côtiers, 0211 other engineering and technologies, 02 engineering and technology, Submersion, 01 natural sciences, Mots-clés : Tempête, 0105 earth and related environmental sciences
Abstract: International audience; Au cours de la dernière décennie, la tempête Xynthia et d'autres ont marqué l'actualité de par leur intensité et les dégâts causés lors de leur passage sur le territoire français. Ces événements peuvent donner l'impression qu'ils n'ont été "jamais vu par le passé", mais le recensement des tempêtes plus anciennes (1953, 1987, 1999…) montre que de tels phénomènes surviennent en fait régulièrement sur le littoral métropolitain. Dès lors, la collecte et l'analyse d'informations historiques apparaissent incontournables pour améliorer la prévention des risques littoraux, en particulier liée à la submersion marine. Afin de mutualiser les informations disponibles en France, une base de données relationnelle et spatiale a été développée au sein de l'IRSN. À ce stade, plus de 650 événements de tempête et/ou de submersion sur le littoral français et des pays voisins ont pu être recensés, sur une période s'étendant de 1500 à nos jours. En parallèle à l'élaboration de cette base de données, un groupe de travail interdisciplinaire s'est constitué. Il intègre des ingénieurs, chercheurs, statisticiens et historiens appartenant à différents organismes. Un axe majeur de travail est l'intégration de nouvelles données historiques issues de diverses archives dans la base de données, ainsi que leur interprétation et la quantification des niveaux marins associés.
Published: 2018
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6. Modelling the retreat of a coastal transverse dune under changing wind conditions

Author: Gabarrou , Sylvain, Le Cozannet , Gonéri, Parteli , Eric J. R., Pedreros , Rodrigo, Guerber , Etienne, Millescamps , Bastien, Oliveros , Carlos, Mallet , Cyrill, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Departamento de Física [Fortaleza], Universidade Federal do Ceará = Federal University of Ceará (UFC), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) ( BRGM ), Universidade Federal do Ceará ( UFC ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -PRES Université Paris-Est-EDF ( EDF ) -Avant création Cerema, LIttoral ENvironnement et Sociétés - UMR 7266 ( LIENSs ), and Université de La Rochelle ( ULR ) -Centre National de la Recherche Scientifique ( CNRS )
Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences
Abstract: International audience; Coastal dunes can move in response to winds and cause serious hazard to human assets. Changes in wind patterns, potentially occurring as a consequence of climate change or variability, could affect rates of aeolian transport and migration velocity of coastal dunes. Understanding the response of coastal dune mobility to changes in transport conditions is a fundamental aspect of coastal zones management. However, most of previous modeling studies were conducted by assuming that aeolian bedforms are subject to a constant wind velocity. In the present work, we perform a modeling study of the mobility of a coastal transverse dune under varying wind velocities based on the example of the Dune du Pilat in Aquitaine. We apply well-established models and empirical formula for aeolian dune migration, including a model previously validated against measurements of real profiles of desert and coastal dunes. The average migration velocity of Pilat dune predicted by the models is about 3m/year, which is in good agreement with in-situ measurements of the dune retreat rates. To test the response of transverse dune mobility to changing winds and the impact of extreme events on dune migration rates, we generate virtual, but still realistic wind time series using a stochastic model. The approach consists in modifying a few parameters of the stochastic model, in order to generate virtual time series with different characteristics than today. The results suggest that more frequent storms have less impacts than more intense winds, but also that both lead to moderate changes in the average dune velocity in
Published: 2018

7. Equilibrium modeling of the beach profile on a macrotidal embayed low tide terrace beach

Author: Clara Lemos, France Floc’h, Marissa Yates, Nicolas Le Dantec, Vincent Marieu, Klervi Hamon, Véronique Cuq, Serge Suanez, Christophe Delacourt, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet HA (Cerema Equipe-projet HA), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université de Brest (UBO), Littoral, Environnement, Télédétection, Géomatique (LETG - Brest), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Caen Normandie (UNICAEN), Université de Nantes (UN)-Université de Nantes (UN), INSU - Service National d'Observation (SNO) DYNALIT, ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), ANR-10-CEPL-0001,COCORISCO,COnnaissance, COmpréhension et gestion des RIsques COtiers(2010), Laboratoire Géosciences Océan ( LGO ), Université de Bretagne Sud ( UBS ) -Université de Brest ( UBO ) -Institut Universitaire Européen de la Mer ( IUEM ), Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ) -Université de Brest ( UBO ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement ( Cerema ) -EDF R&D ( EDF R&D ), EDF ( EDF ) -EDF ( EDF ), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Eau Mer et Fleuves ( Cerema Direction Eau Mer et Fleuves ), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement ( Cerema ), Environnements et Paléoenvironnements OCéaniques ( EPOC ), Observatoire aquitain des sciences de l'univers ( OASU ), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -École pratique des hautes études ( EPHE ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Brest ( UBO ), Littoral, Environnement, Télédétection, Géomatique ( LETG - Brest ), Littoral, Environnement, Télédétection, Géomatique ( LETG ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Université d'Angers ( UA ) -Université de Nantes ( UN ) -École pratique des hautes études ( EPHE ) -Université de Brest ( UBO ) -Université de Rennes 2 ( UR2 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Caen Normandie ( UNICAEN ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ), ANR-10-LABX-0019/10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean ( 2010 ), and ANR-10-CEPL-0001,COCORISCO,COnnaissance, COmpréhension et gestion des RIsques COtiers ( 2010 )
Subjects: 010504 meteorology & atmospheric sciences, Equilibrium model, Intertidal zone, Forcing (mathematics), 010502 geochemistry & geophysics, Oceanography, Atmospheric sciences, 01 natural sciences, Cross-shore processes, [ SDE.IE ] Environmental Sciences/Environmental Engineering, Macrotidal, [ SDE ] Environmental Sciences, 14. Life underwater, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Wave power, geography, geography.geographical_feature_category, [ SDU.STU.GM ] Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDE.IE]Environmental Sciences/Environmental Engineering, Elevation, Intertidal profile, Equilibrium modeling, Water level, Terrace (geology), Inflection point, [SDE]Environmental Sciences, Low tide terrace, Geology
Abstract: International audience; Eleven-year long time series of monthly beach profile surveys and hourly incident wave conditions are analyzed for a macrotidal Low Tide Terrace beach. The lower intertidal zone of the beach has a pluriannual cycle, whereas the upper beach profile has a predominantly seasonal cycle. An equilibrium model is applied to study the variation of the contour elevation positions in the intertidal zone as a function of the wave energy, wave power, and water level. When forcing the model with wave energy, the predictive ability of the equilibrium model is around 60% in the upper intertidal zone but decreases to 40% in the lower intertidal zone. Using wave power increases the predictive ability up to 70% in both the upper and lower intertidal zones. However, changes around the inflection point are not well predicted. The equilibrium model is then extended to take into account the effects of the tide level. The initial results do not show an increase in the predictive capacity of the model, but do allow the model free parameters to represent more accurately the values expected in a macrotidal environment. This allows comparing the empirical model calibration in different tidal environment. The interpretation of the model free parameter variation across the intertidal zone highlights the behavior of the different zones along the intertidal beach profile. This contributes to a global interpretation of the four model parameters for beaches with different tidal ranges, and therefore to a global model applicable at a wide variety sites.
Published: 2018
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8. A coupled wave–current–sediment transport model for an estuarine system: Application to the Río de la Plata and Montevideo Bay

Author: J.C. Ismael Piedra-Cueva, Pablo Santoro, Pablo Tassi, Nicolas Huybrechts, Mónica Fossati, Damien Pham Van Bang, Simulation et Traitement de l'information pour l'Exploitation des systèmes de Production (EDF R&D STEP), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), Universidad de la República [Montevideo] (UCUR), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Centre d'Etudes et d'Expertises sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet HA (Cerema Equipe-projet HA), and Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)
Subjects: geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Advection, [SDE.IE]Environmental Sciences/Environmental Engineering, Applied Mathematics, Sediment, Estuary, 010502 geochemistry & geophysics, 01 natural sciences, Current (stream), Water column, Oceanography, 13. Climate action, Modeling and Simulation, Environmental science, Coastal engineering, 14. Life underwater, Bay, Sediment transport, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Modelling the hydrodynamics and fine-sediment dynamics in estuarine environments is important for coastal engineering design and environmental assessment. This paper presents the application of a coupled wave–current–sediment transport model to a complex estuarine system with high spatial resolution in a harbour area. The case study was the Rio de la Plata, with a focus on the Montevideo Bay area. We used a bidimensional depth-averaged approach, and the sediment transport modelling focused on fine cohesive sediments. The model considers realistic forcings, allows for the simulation of complex geometries such as those present in harbour basins and is capable of providing long-term environmental simulations (on the order of several years) within reasonable computational times. The model results are in good agreement with the measured data and satisfactorily represent the main features of the flow and sediment dynamics of the Rio de la Plata. The effect of the internal coupling on the hydrodynamic results is analysed, and the computational times with various coupling alternatives are discussed. The dynamics of fine sediment in Montevideo Bay were analysed based on the model results. The current-induced bottom shear stress results are relevant for representing the permanent suspended sediment concentrations, whereas the wave-induced bottom shear stress is fundamental for reproducing the main resuspension events during storm conditions. The suspended fine-sediment dynamics in the estuary are strongly controlled by the sediment exchange between the bed and water column, whereas inside Montevideo Bay, the dynamics are controlled mainly by advection of sediment originating from the nearby coastal area.
Published: 2017
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9. Analysis of the linear version of a highly dispersive potential water wave model using a spectral approach in the vertical

Author: Marissa Yates, Cécile Raoult, Michel Benoit, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet HA (Cerema Equipe-projet HA), and Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)
Subjects: Chebyshev polynomials, 010504 meteorology & atmospheric sciences, Wave propagation, [SDE.MCG]Environmental Sciences/Global Changes, General Physics and Astronomy, 01 natural sciences, 010305 fluids & plasmas, Wave model, Dispersion relation, Linear waves, Optics, 0103 physical sciences, Wavenumber, 0105 earth and related environmental sciences, Mathematics, business.industry, [SDE.IE]Environmental Sciences/Environmental Engineering, Applied Mathematics, Mathematical analysis, 6. Clean water, Water waves, Computational Mathematics, Waves and shallow water, Wave shoaling, Potential theory, Modeling and Simulation, Roseau profile, Reflection (physics), business
Abstract: International audience; h i g h l i g h t s • Highly dispersive potential flow model for water wave propagation. • Linear dispersion relation accurate in very deep water conditions (kh up to 100). • Accurate prediction of wave kinematics (orbital velocities) in deep water. • Validation of linear shoaling properties of the model. • Good prediction of reflected and transmitted waves on a Roseau-type bottom profile. a b s t r a c t The properties and accuracy of the linearized version of the fully dispersive and nonlinear wave model developed in Yates and Benoit (2015) and Raoult et al. (2016) are analyzed for both flat and variable bottom bathymetries. This model considers only a single layer of fluid and uses a basis of orthogonal Chebyshev polynomials to project the vertical structure of the potential. This approach results in an exponential convergence rate with the maximum degree of the Chebyshev polynomial, denoted N T , while only first-and second-order derivatives in space need to be evaluated. For the constant water depth case, the linear dispersion relation of the model is derived analytically, and expressions are established for N T ranging from 2 to 15. The analysis shows a rapid increase in accuracy in the deep water range with increasing N T. For instance, the relative error in the calculated wave celerity (in comparison with Stokes' analytical solution) remains smaller than 2.5% for deep water cases with kh up to 100 using N T ≥ 9 (k and h are the representative wavenumber and water depth, respectively). The wave kinematics, vertical profiles of the horizontal and vertical orbital velocities, converge to the Stokes profiles for kh up to 60 when using a sufficiently high value of N T. The vertically-averaged relative errors of the horizontal and vertical velocities remain below 6% and 3%, respectively, for kh up to 60 when using N T ≥ 11. The presented model shows better dispersive properties in deep water than several high-order Boussinesq-type models. For variable bottom bathymetries, the shoaling properties of the model are studied numerically, exhibiting good agreement with results from Stokes linear theory in the case of mild bottom slopes, using a sufficiently high value of N T with respect to the offshore relative water depth. For an offshore water depth of kh = 10 (i.e. more than 3 times the deep water limit), accurate wave heights in shallow water (kh = 0.25) are obtained with N T = 6 (or higher). Finally, the linear version of the model is validated with comparisons to analytical solutions of the reflection and transmission coefficients of regular waves over Roseau-type bathymetric profiles. Two bottom profiles are considered, including one with a steep slope, whose maximum value reaches about 1:0.7 (i.e. an angle of about 54.9 deg.). Using N T = 7, small differences (
Published: 2017
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10. Discussion of 'Laboratory Study on 3D Flow Structures Induced by Zero-Height Side Weir and Implications for 1D Modeling' by Giovanni Michelazzo, Hocine Oumeraci, and Enio Paris

Author: Michel Pirotton, K. El Kadi Abderrezzak, Benjamin Dewals, Pierre Archambeau, Ismail Rifai, Damien Violeau, Sébastien Erpicum, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), and Université de Liège
Subjects: Hydrology, Mechanical Engineering, 0208 environmental biotechnology, Zero (complex analysis), Geometry, 02 engineering and technology, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], 020801 environmental engineering, [SDE]Environmental Sciences, Weir, ComputingMilieux_MISCELLANEOUS, Geology, Water Science and Technology, Civil and Structural Engineering
Abstract: International audience
Published: 2017
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11. Unified semi-analytical wall boundary conditions in SPH: analytical extension to 3-D

Author: Damien Violeau, Arno Mayrhofer, Martin Ferrand, François-Xavier Morel, Christophe Kassiotis, University of Natural Resources and Life Sciences [Wien] ( BOKU ), Université médicale de Vienne, Autriche, Laboratoire de Psychopathologie et Processus de Santé ( LPPS - EA 4057 ), Université Paris Descartes - Paris 5 ( UPD5 ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -PRES Université Paris-Est-EDF ( EDF ) -Avant création Cerema, University of Natural Resources and Life Sciences [Wien] (BOKU), Laboratoire de Psychopathologie et Processus de Santé (LPPS - EA 4057), Université Paris Descartes - Paris 5 (UPD5), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), and École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema
Subjects: [ SPI.MECA ] Engineering Sciences [physics]/Mechanics [physics.med-ph], Applied Mathematics, Computation, Numerical analysis, Boundary (topology), Smoothed particle hydrodynamics, Geometry, Context (language use), [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph], Domain (mathematical analysis), [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], Smoothed-particle hydrodynamics, [SPI]Engineering Sciences [physics], Kernel (statistics), [ SPI ] Engineering Sciences [physics], [ SPI.MECA.MEFL ] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], Fluid mechanics, Applied mathematics, Unified semi-analytical, Boundary value problem, ComputingMilieux_MISCELLANEOUS, Mathematics
Abstract: Solid wall boundary conditions have been an area of active research within the context of Smoothed Particle Hydrodynamics (SPH) for quite a while. Ferrand et al. (Int. J. Numer. Methods Fluids 71(4), 446---472, 2012) presented a novel approach using a renormalization factor in the SPH approximation. The computation of this factor depends on an integral along the boundary of the domain and in their original paper Ferrand et al. gave an analytical formulation for the 2-D case using the Wendland kernel. In this paper the formulation will be extended to 3-D, again providing analytical formulae. Due to the boundary being two dimensional a domain decomposition algorithm needs to be employed in order to obtain special integration domains. For these the analytical formulae will be presented when using the Wendland kernel. The algorithm presented within this paper is applied to several academic test-cases for which either analytical results or simulations with other methods are available. It will be shown that the present formulation produces accurate results and provides a significant improvement compared to approximative methods.
Published: 2014
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12. Validation of a fully nonlinear and dispersive wave model with laboratory non-breaking experiments

Author: Marissa Yates, Michel Benoit, Cécile Raoult, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet HA (Cerema Equipe-projet HA), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (LHSV), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -PRES Université Paris-Est-EDF ( EDF ) -Avant création Cerema, Laboratoire d'Informatique de Robotique et de Microélectronique de Montpellier ( LIRMM ), Université de Montpellier ( UM ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement ( Cerema ) -EDF R&D ( EDF R&D ), and EDF ( EDF ) -EDF ( EDF )
Subjects: Environmental Engineering, 010504 meteorology & atmospheric sciences, Wave propagation, [SDE.MCG]Environmental Sciences/Global Changes, Ocean Engineering, 01 natural sciences, [ SDE.IE ] Environmental Sciences/Environmental Engineering, 010305 fluids & plasmas, potential theory, Wave model, symbols.namesake, 0103 physical sciences, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Dispersion (water waves), 0105 earth and related environmental sciences, Mathematics, Stokes drift, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Mechanics of the fluids [physics.class-ph], [SDE.IE]Environmental Sciences/Environmental Engineering, water waves, Breaking wave, dispersive, Mechanics, [ SDE.MCG ] Environmental Sciences/Global Changes, Classical mechanics, Surface wave, Free surface, Wave shoaling, symbols, nonlinear, Zakharov equations
Abstract: International audience; Abstract With the objective of modeling coastal wave dynamics taking into account nonlinear and dispersive effects, a highly accurate nonlinear potential flow model was developed. The model is based on the time evolution of two surface quantities: the free surface position and the free surface velocity potential. A spectral approach is used to resolve vertically the velocity potential in the domain, by decomposing the potential using an orthogonal basis of Chebyshev polynomials. With this approach, a wide range of relative water depths can be simulated, as demonstrated here with the propagation of nonlinear regular waves over a flat bottom with kh = 2π and 4π (where k is the wave number and h the water depth). The model is then validated by comparing the simulation results to experimental data for four non-breaking wave test cases: (1) nonlinear dynamics of a wave train generated by a piston-type wavemaker in constant water depth, (2) shoaling of a regular wave train on beach with constant slope up to the breaking point, (3) propagation of regular waves over a submerged bar, and (4) propagation of nonlinear irregular waves over a barred beach. The test cases show the ability of the model to reproduce well nonlinear wave interactions and the dynamics of higher-order bound and free harmonics. The simulation results agree well with the experimental data, confirming the model's ability to simulate accurately nonlinear and dispersive effects for non-breaking waves.
Published: 2016
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13. Modelling river bank erosion using a 2D depth-averaged numerical model of flow and non-cohesive, non-uniform sediment transport

Author: Pablo Tassi, Riadh Ata, Jean-Michel Hervouet, Kamal El Kadi Abderrezzak, Andres Die Moran, Simulation et Traitement de l'information pour l'Exploitation des systèmes de Production (EDF R&D STEP), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), and École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema
Subjects: Engineering, business.industry, 0208 environmental biotechnology, [INFO.INFO-CE]Computer Science [cs]/Computational Engineering, Finance, and Science [cs.CE], 02 engineering and technology, 6. Clean water, Angle of repose, 020801 environmental engineering, Unstructured grid, Flume, Cohesion (geology), Geotechnical engineering, business, Bank failure, Scale model, Sediment transport, Bank erosion, ComputingMilieux_MISCELLANEOUS, Water Science and Technology
Abstract: Bank erosion can be an important form of morphological adjustment in rivers. With the advances made in computational techniques, two-dimensional (2D) depth-averaged numerical models have become valuable tools for resolving many engineering problems dealing with sediment transport. The objective of this research work is to present a simple, new, bank-erosion operator that is integrated into a 2D Saint-Venant-Exner morphodynamic model. The numerical code is based on an unstructured grid of triangular elements and finite-element algorithms. The slope of each element in the grid is compared to the angle of repose of the bank material. Elements for which the slope is too steep are tilted to bring them to the angle of repose along a horizontal axis defined such that the volume loss above the axis is equal to the volume gain below, thus ensuring mass balance. The model performance is assessed using data from laboratory flume experiments and a scale model of the Old Rhine. For the flume experiment case with uniform bank material, relevant results are obtained for bank geometry changes. For the more challenging case (i.e. scale model of the Old Rhine with non-uniform bank material), the numerical model is capable of reproducing the main features of the bank failure, induced by the newly designed groynes, as well as the transport of the mobilized sediment material downstream. Some deviations between the computed results and measured data are, however, observed. They are ascribed to the effects of three-dimensional (3D) flow structures, pore pressure and cohesion, which are not considered in the present 2D model.
Published: 2016
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14. Applying Riemann solvers to open boundaries in free surface and confined flows

Author: Joly, Antoine, Violeau, Damien, Leroy, Agnès, Ferrand, Martin, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, and Mécanique des Fluides, Energies et Environnement (EDF R&D MFEE)
Subjects: [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract: International audience; Due to the Lagrangian nature of SPH, dealing with open boundaries (which are intrinsically Eulerian) is a challenging issue. This issue has recently been addressed in the Unified Semi-Analytical Boundaries framework [1], where it has been shown how to properly deal with mass fluxes at the open boundaries. However imposing both velocities and pressures on the open boundaries will over-constrain the problem, and in most cases only one of these quantities will be known. Therefore, Riemann Solvers can be used to calculate and prescribe compatible fields at the open boundaries. These compatible fields allow therefore complex boundary conditions to be imposed.
Published: 2016

15. Parallel SOR methods with a parabolic-diffusion acceleration technique for solving an unstructured-grid Poisson equation on 3D arbitrary geometries

Author: Kim Dan Nguyen, M. A. Uh Zapata, D. Pham Van Bang, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), and École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema
Subjects: Mathematical optimization, Computer science, Mechanical Engineering, Linear system, Computational Mechanics, Parallel algorithm, Message Passing Interface, Energy Engineering and Power Technology, Aerospace Engineering, Domain decomposition methods, Solver, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, Unstructured grid, Computational science, 010101 applied mathematics, [SPI.GCIV]Engineering Sciences [physics]/Civil Engineering, Successive over-relaxation, Mechanics of Materials, 0103 physical sciences, [SDE]Environmental Sciences, 0101 mathematics, Poisson's equation, ComputingMilieux_MISCELLANEOUS
Abstract: This paper presents a parallel algorithm for the finite-volume discretisation of the Poisson equation on three-dimensional arbitrary geometries. The proposed method is formulated by using a 2D horizontal block domain decomposition and interprocessor data communication techniques with message passing interface. The horizontal unstructured-grid cells are reordered according to the neighbouring relations and decomposed into blocks using a load-balanced distribution to give all processors an equal amount of elements. In this algorithm, two parallel successive over-relaxation methods are presented: a multi-colour ordering technique for unstructured grids based on distributed memory and a block method using reordering index following similar ideas of the partitioning for structured grids. In all cases, the parallel algorithms are implemented with a combination of an acceleration iterative solver. This solver is based on a parabolic-diffusion equation introduced to obtain faster solutions of the linear systems arising from the discretisation. Numerical results are given to evaluate the performances of the methods showing speedups better than linear.
Published: 2016
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16. The hydrodynamic, sea-state and infrastructures platform developed by Saint-Venant Hydraulics Laboratory and Cerema: a special focus on the TELEMAC2D surge levels numerical model of the Atlantic Ocean, the Channel and the North Sea

Author: Laborie, Vanessya, Sergent, Philippe, Levy, Florence, Frau, Roberto, Weiss, Jérome, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Centre d'Etudes et d'Expertises sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet HA (Cerema Equipe-projet HA), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), École des hautes études en sciences sociales (EHESS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), and TELEMAC-MASCARET Core Group
Subjects: [SDE.IE]Environmental Sciences/Environmental Engineering, [SDE]Environmental Sciences, Ingenieurwissenschaften (620), [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience
Published: 2015

17. Modélisation des interactions dans une ferme de systèmes houlomoteurs avec prise en compte de la bathymétrie

Author: Charrayre, François, Benoit, Michel, Peyrard, Christophe, Babarit, Aurélien, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Laboratoire de recherche en Hydrodynamique, Énergétique et Environnement Atmosphérique (LHEEA), and École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SPI.NRJ]Engineering Sciences [physics]/Electric power, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract: International audience; Un champ de vagues interagit avec son environnement, qu'il soit naturel (falaise, bathymetrie, ...)ou artificiel (corps ottants, digues, ...). Ainsi, la presence d'une ferme houlomotrice aura un impactsur le champ de houle. A contrario, on peut aussi dire que le rendement des systemes houlomoteursdepend de leurs positions et du champ de vagues incident.Nous proposons ici une methode dont le but est de calculer rapidement ces interactions entre lessystemes houlomoteurs, tout en prenant en compte la bathymetrie qui peut avoir un impact nonnegligeable sur le champ de vagues. Une methodologie de couplage entre un modele local de radiation/diffraction autour de chaque WEC, et un modele de propagation a fond variable est developpee,puis validee dans un cas a fond plat. Appliquee tout d'abord a une houle incidente monochromatique,cette demarche permet aussi de faire des etudes pour des etats de mer irreguliers multidirectionnels.
Published: 2014

18. Two-dimensional modeling of fine sediment transport with mixed sediment and consolidation: Application to the Gironde Estuary, France

Author: Sylvain Orseau, Fabrice Klein, Pablo Tassi, Damien Pham Van Bang, Nicolas Huybrechts, Centre d'Etudes et d'Expertises sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet HA (Cerema Equipe-projet HA), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Roberval (Roberval), Université de Technologie de Compiègne (UTC), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet HA (Cerema Equipe-projet HA), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), Centre Eau Terre Environnement [Québec] (INRS - ETE), and Institut National de la Recherche Scientifique [Québec] (INRS)
Subjects: Stratigraphy, 0207 environmental engineering, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Numerical modeling, Gironde estuary, 14. Life underwater, Turbidity, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 020701 environmental engineering, Squat effect, 0105 earth and related environmental sciences, Hydrology, geography, geography.geographical_feature_category, Consolidation (soil), Discharge, [SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment, Estuary, Geology, Dimensional modeling, Sediment transport, Opentelemac, Gironde, 13. Climate action, Environmental science, Mixed sediment
Abstract: International audience; In order to optimize ship navigation in the macrotidal Gironde Estuary, a recent project funded by the port of Bordeaux aims at better understand and forecast hydrodynamic and fine sediment transport within the estuary. In the framework of this project, a two-dimensional hydro-sedimentary model is built. The model includes hydrodynamic forcings, mixed-sediment transport, and consolidation processes. The harmonic analysis of the astronomical tides reveals a strong distortion of the tidal wave inducing the growth of overtide constituents and the non-significant effect of tide-surge interactions in annual-scale prediction. Depending on hydrological conditions, river discharge can considerably alter the model accuracy due to the migration of the turbidity maximum zone modifying the bottom roughness. Comparison with measurements shows the ability of the model to reproduce suspended-sediment concentrations in the central Estuary. Sensitivity of the model to sediment features has also been discussed in regard of suspended-sediment concentrations and fluid mud deposits. The model will be further coupled with ship squat predictions and a morphodynamic model.p { margin-bottom: 0.25 cm; line-height: 115%; }
Published: 2021
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19. Modelling sedimentation-consolidation in the framework of a one-dimensional two-phase flow model

Author: Kim Dan Nguyen, Julien Chauchat, Sylvain Guillou, Damien Pham Van Bang, Laboratoire des écoulements géophysiques et industriels ( LEGI ), Université de Grenoble-Alpes-Institut polytechnique de Grenoble - Grenoble Institute of Technology ( Grenoble INP ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Universitaire des Sciences Appliquées de Cherbourg ( LUSAC ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -PRES Université Paris-Est-EDF ( EDF ) -Avant création Cerema, Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), and École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema
Subjects: 010504 meteorology & atmospheric sciences, Consolidation (soil), [SDE.IE]Environmental Sciences/Environmental Engineering, Effective stress, Momentum transfer, 0207 environmental engineering, 02 engineering and technology, Mechanics, 01 natural sciences, [ SDE.IE ] Environmental Sciences/Environmental Engineering, [ SDE ] Environmental Sciences, Settling, Drag, [SDE]Environmental Sciences, Solid phases, Two-phase flow, Statistical physics, 020701 environmental engineering, Data flow model, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering, Mathematics
Abstract: International audience; A one-dimensional vertical two-phase flow model for sedimentation-consolidation process is presented. The model is based on solving the continuity and momentum equations for both fluid and solid phases. In the non-cohesive case, the momentum transfer between the two phases is reduced to the drag force around a single particle modified to take the hindrance effects into account. In the cohesive case, Darcy-Gersevanov's law is used for the closure of the momentum transfer between the two phases and the concept of "effective stress" is introduced to take into account the bed structuring. These closure laws are validated against high resolution experimental data in terms of settling curves and concentration profiles. The reliability of the model is illustrated from an analysis of the momentum balances at different stages during the process. Finally, the proposed closure laws and numerical algorithms are shown to be able to quantitatively reproduce sedimentation of non-cohesive and sedimentation- consolidation of cohesive sediments, including mud.
Published: 2013
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20. Nonlinear time‐domain wave‐structure interaction: A parallel fast integral equation approach

Author: Michel Benoit, Jeffrey C. Harris, Stephan T. Grilli, Emmanuel Dombre, Konstantin Kuznetsov, École des Ponts ParisTech (ENPC), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), University of Rhode Island (URI), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), École des Ponts ParisTech (ENPC)-EDF R&D (EDF R&D), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, [SDE.IE]Environmental Sciences/Environmental Engineering, Applied Mathematics, Mechanical Engineering, Mathematical analysis, Computational Mechanics, 01 natural sciences, Integral equation, 010305 fluids & plasmas, Computer Science Applications, Physics::Fluid Dynamics, 010101 applied mathematics, Nonlinear system, Mechanics of Materials, Free surface, 0103 physical sciences, Fluid–structure interaction, Potential flow, Time domain, 0101 mathematics, Multipole expansion, Boundary element method
Abstract: International audience; We report on the development and validation of a new Numerical Wave Tank (NWT) solving fully nonlinear potential flow (FNPF) equations, as a more efficient variation of Grilli et al.'s NWT [Grilli et al., A fully nonlinear model for three-dimensional overturning waves over arbitrary bottom, International Journal for Numerical Methods in Fluids 35 (2001) 829-867], which was successful at modeling many wave phenomena, including landslide-generated tsunamis, rogue waves, and the initiation
Published: 2021
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21. Sediment transport modelling : relaxation schemes for Saint-Venant - Exner and three layer models

Author: Magali Jodeau, Emmanuel Audusse, Christophe Berthon, Jacques Sainte-Marie, Jan Giesselmann, Christophe Chalons, Nicole Goutal, Georges Sadaka, Olivier Delestre, Laboratoire Analyse, Géométrie et Applications ( LAGA ), Université Paris 8 Vincennes-Saint-Denis ( UP8 ) -Université Paris 13 ( UP13 ) -Université Sorbonne Paris Cité ( USPC ) -Institut Galilée-Centre National de la Recherche Scientifique ( CNRS ), Nonlinear Analysis for Biology and Geophysical flows ( BANG ), Laboratoire Jacques-Louis Lions ( LJLL ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ) -Inria Paris-Rocquencourt, Institut National de Recherche en Informatique et en Automatique ( Inria ) -Institut National de Recherche en Informatique et en Automatique ( Inria ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Énergétique Moléculaire et Macroscopique, Combustion ( EM2C ), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Jean Alexandre Dieudonné ( JAD ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -PRES Université Paris-Est-EDF ( EDF ) -Avant création Cerema, Numerical Analysis, Geophysics and Ecology ( ANGE ), Department of Mathematics [Stuttgart], University of Stuttgart, Laboratoire Amiénois de Mathématique Fondamentale et Appliquée ( LAMFA ), Université de Picardie Jules Verne ( UPJV ) -Centre National de la Recherche Scientifique ( CNRS ), Mathématiques Appliquées à Paris 5 ( MAP5 - UMR 8145 ), Université Paris Descartes - Paris 5 ( UPD5 ) -Institut National des Sciences Mathématiques et de leurs Interactions-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Analyse, Géométrie et Applications (LAGA), Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris 13 (UP13)-Institut Galilée-Centre National de la Recherche Scientifique (CNRS), Nonlinear Analysis for Biology and Geophysical flows (BANG), Laboratoire Jacques-Louis Lions (LJLL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Inria Paris-Rocquencourt, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Laboratoire d'Énergétique Moléculaire et Macroscopique, Combustion (EM2C), CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris Saclay (COmUE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Mathématiques - Analyse, Probabilités, Modélisation - Orléans (MAPMO), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Jean Alexandre Dieudonné (JAD), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (LHSV), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Modeling, analysis and control in computational structural dynamics (MACS), Inria Paris-Rocquencourt, Centre d'Études Techniques Maritimes et Fluviales (CETMEF), Avant création Cerema, Laboratoire Amiénois de Mathématique Fondamentale et Appliquée (LAMFA), Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS), CEMRACS, PEPS, EDF, Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris 13 (UP13)-Institut Galilée-Université Sorbonne Paris Cité (USPC)-Centre National de la Recherche Scientifique (CNRS), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), Numerical Analysis, Geophysics and Ecology (ANGE), Mathématiques Appliquées Paris 5 (MAP5 - UMR 8145), Université Paris Descartes - Paris 5 (UPD5)-Institut National des Sciences Mathématiques et de leurs Interactions (INSMI)-Centre National de la Recherche Scientifique (CNRS), Université Paris 8 Vincennes-Saint-Denis (UP8)-Centre National de la Recherche Scientifique (CNRS)-Institut Galilée-Université Paris 13 (UP13), Université Paris Saclay (COmUE)-Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec, Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), and Laboratoire Amiénois de Mathématique Fondamentale et Appliquée - UMR CNRS 7352 (LAMFA)
Subjects: T57-57.97, Applied mathematics. Quantitative methods, Sediment, Flux, 010103 numerical & computational mathematics, Function (mathematics), Mechanics, relaxation schemes, Exner equation, 01 natural sciences, Stability (probability), 010101 applied mathematics, QA1-939, Relaxation (approximation), 0101 mathematics, Sediment transport, Sediment transport modelling, Geology, Simulation, shallow water flows, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], Mathematics, Bed load
Abstract: International audience; In this note we are interested in the modelling of sediment transport phenomena. We mostly focus on bedload transport and we do not consider suspension sediment processes. We first propose a numerical scheme for the classical Saint-Venant - Exner model. It is based on a relaxation approach for the whole system and it works with all sediment flux function. The stability of the scheme is investigated and some numerical tests are proposed. We exhibit that this coupled approach is more stable than the splitting approach that is mostly used in industrial softwares. Then we derive an original three layers model in order to overcome the difficulties that are encountered when using the classical Exner approach and we present a related relaxation model.
Published: 2012
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22. Simulation of dredged sediment releases into homogeneous water using a two-phase model

Author: Damien Pham Van Bang, Florence Levy, Sylvain Guillou, Julien Chauchat, Kim Dan Nguyen, Duc Hau Nguyen, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -PRES Université Paris-Est-EDF ( EDF ) -Avant création Cerema, Laboratoire Universitaire des Sciences Appliquées de Cherbourg ( LUSAC ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ), Laboratoire des écoulements géophysiques et industriels ( LEGI ), Université de Grenoble-Alpes-Institut polytechnique de Grenoble - Grenoble Institute of Technology ( Grenoble INP ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Computer simulation, Sediment, 01 natural sciences, 010305 fluids & plasmas, Plume, Current (stream), Dredging, Settling, Phase (matter), 0103 physical sciences, Geotechnical engineering, 14. Life underwater, Sediment transport, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology
Abstract: Dredging operations of navigation channels and harbours are regularly planned in order to maintain the nautical depth and to ensure the navigation safety. Depending on the quality of the dredged material (fixed by the Oslo convention, 1972), dredged sediments can be released into the sea or stored at the Earth’s surface to be cleaned up. The present study deals with release operations. We simulate the complete process (generation and settling of a sediment plume, propagation of a density current on the bottom) using a two-phase flow model. We show that in this case, the sediment (or solid) phase strongly differs from the motion of the water (or fluid) phase. Comparisons between numerical results and experiments are carried out in order to illustrate the effects of sediment diameter, initial concentration, and ambient current on the plume dynamics and on the density current. We obtain a correct agreement with experiments for the specific release case.
Published: 2012
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23. Guest Editors' note

Author: Kamal El Kadi Abderrezzak, Jorge D. Abad, Eddy J. Langendoen, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant Laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-PRES Université Paris-Est-EDF (EDF)-Avant création Cerema, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: Environmental Engineering, 010504 meteorology & atmospheric sciences, 0207 environmental engineering, 02 engineering and technology, Management, Monitoring, Policy and Law, 01 natural sciences, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], [SDE]Environmental Sciences, Environmental Chemistry, 020701 environmental engineering, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering
Abstract: International audience
Published: 2014
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24. Equilibrium shoreline response: Observations and modeling

Author: William C. O'Reilly, Robert T. Guza, Marissa Yates, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics ( Saint-Venant ), École des Ponts ParisTech ( ENPC ) -Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement ( Cerema ) -EDF R&D ( EDF R&D ), and EDF ( EDF ) -EDF ( EDF )
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Meteorology, [SDE.MCG]Environmental Sciences/Global Changes, Soil Science, Aquatic Science, Oceanography, Atmospheric sciences, 01 natural sciences, [ SDE.IE ] Environmental Sciences/Environmental Engineering, 010305 fluids & plasmas, Incident wave, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Sea level, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Shore, geography, Plage, geography.geographical_feature_category, Ecology, [SDE.IE]Environmental Sciences/Environmental Engineering, Bedrock, Paleontology, Forestry, Storm, [ SDE.MCG ] Environmental Sciences/Global Changes, Geophysics, 13. Climate action, Space and Planetary Science, Environmental science, Accretion (coastal management), Free parameter
Abstract: International audience; [1] Shoreline location and incident wave energy, observed for almost 5 years at Torrey Pines beach, show seasonal fluctuations characteristic of southern California beaches. The shoreline location, defined as the cross-shore position of the mean sea level contour, retreats by almost 40 m in response to energetic winter waves and gradually recovers during low-energy summer waves. Hourly estimates of incident wave energy and weekly to monthly surveys of the shoreline location are used to develop and calibrate an equilibrium-type shoreline change model. By hypothesis, the shoreline change rate depends on both the wave energy and the wave energy disequilibrium with the shoreline location. Using calibrated values of four model free parameters, observed and modeled shoreline location are well correlated at Torrey Pines and two additional survey sites. Model free parameters can be estimated with as little as 2 years of monthly observations or with about 5 years of ideally timed, biannual observations. Wave energy time series used to calibrate and test the model must resolve individual storms, and model performance is substantially degraded by using weekly to monthly averaged wave energy. Variations of free parameter values between sites may be associated with variations in sand grain size, sediment availability, and other factors. The model successfully reproduces shoreline location for time periods not used in tuning and can be used to predict beach response to past or hypothetical future wave climates. However, the model will fail when neglected geologic factors are important (e.g., underlying bedrock limits erosion or sand availability limits accretion).
Published: 2009
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25. Energy stable and linearly well-balanced numerical schemes for the non-linear Shallow Water equations with Coriolis force

Author: Audusse, Emmanuel, Dubos, Virgile, Gaveau, Noémie, Penel, Yohan, Laboratoire Analyse, Géométrie et Applications (LAGA), Université Paris 8 Vincennes-Saint-Denis (UP8)-Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Institut Denis Poisson (IDP), Université d'Orléans (UO)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Numerical Analysis, Geophysics and Ecology (ANGE), Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jacques-Louis Lions (LJLL (UMR_7598)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), Centre National de la Recherche Scientifique (CNRS)-Université de Tours (UT)-Université d'Orléans (UO), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Centre National de la Recherche Scientifique (CNRS)-Université de Tours-Université d'Orléans (UO)
Subjects: Physics::Atmospheric and Oceanic Physics, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA]
Abstract: This work is dedicated to the analysis of a class of energy stable and linearly well-balanced numerical schemes dedicated to the non-linear Shallow Water equations with Coriolis force. The proposed algorithms rely on colocated finite volume approximations formulated on cartesian geometries. They involve appropriate diffusion terms in the numerical fluxes, expressed as discrete versions of the linear geostrophic equilibrium. We show that the resulting methods ensure semi-discrete energy estimates and numerical results show a very clear improvement around the nonlinear geostrophic equilibrium when compared to those of classic Godunov-type schemes.
Published: 2022

26. Submersions marines sur le littoral atlantique français : 700 ans d’archives sociétales et environnementales pour une meilleure connaissance et gestion du risque

Author: Maanan, Mohamed, Athimon, Emmanuelle, Pouzet, Pierre, Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Nantes (UN)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, marine submersions, adaptation sociale, [SDE.MCG]Environmental Sciences/Global Changes, ouest de la France, social adaptation, submersions marines, [SHS.GEO]Humanities and Social Sciences/Geography, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDE.ES]Environmental Sciences/Environmental and Society, western France
Abstract: International audience; This research, funded by La Fondation de France, aims to: 1) retrace thehistory of marine submersion in western France using multidisciplinary approaches, 2)assess the quantitative and qualitative impacts of these events on coastal societies, and3) define the notion of “societal resilience” through the historical prism. Themethodology is based on an interdisciplinary approach integrating sedimentology (21sedimentary cores were taken) and climate history (19 691 unpublished historicaldocuments were examined and analyzed). The spatial and temporal framework of thestudy is the French Atlantic coast, and it covers a period ranging from the 14th centuryto the present day. The coupling of sedimentological data with historical archives hasmade it possible to characterize fifteen storms with marine submersions. The results ofthis research bear witness to the adaptability of populations and their tolerance to therisk of marine submersion throughout history. These different approaches make itpossible to increase knowledge of coastal hazards, to contribute to their prevention andto propose prospective tools for the management of coastal risks.; Cette recherche, financée par la Fondation de France, avait pour objectifs :1) de retracer l’histoire des submersions marines dans l’ouest de la France à l’aided’approches pluridisciplinaires, 2) d’évaluer les impacts quantitatifs et qualitatifs deces évènements sur les sociétés littorales, et 3) de définir la notion de « résiliencesociétale » sous le prisme historique. La méthodologie repose sur une approcheinterdisciplinaire intégrant la sédimentologie (21 carottes sédimentaires ont étéprélevées) et l’histoire du climat (19 691 documents historiques ont été dépouillés etanalysés). Le cadre spatio-temporel de l'étude sur la façade atlantique française etcouvre une période allant du XIVe siècle à nos jours. Le couplage des donnéessédimentologiques avec les archives historiques a permis de caractériser quinzetempêtes avec submersions marines. Les résultats de cette recherche témoignent del’adaptabilité des populations et de leur tolérance au risque de submersion marine àtravers l’histoire. Ces différentes approches permettent d’accroître la connaissance desaléas côtiers, de contribuer à leur prévention et de proposer des outils prospectifs pourla gestion des risques littoraux.
Published: 2021
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27. Time-scales of a Dune-Beach System and Implications for Shoreline Modelling

Author: Jennifer Montaño, Giovanni Coco, Teddy Chataigner, Marissa Yates, Nicolas Le Dantec, Serge Suanez, Laura Cagigal, France Floc'h, Ian Townend, School of Environment, Faculty of Science, University of Auckland, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire Géosciences Océan (LGO), Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Littoral, Environnement, Télédétection, Géomatique (LETG - Brest), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Caen Normandie (UNICAEN), Université de Nantes (UN)-Université de Nantes (UN), The University of Southampton (Faculty of Engineering and the Environement), CNRS-INSU (SNO - DYNALIT), ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-Université de Nantes (UN)-École pratique des hautes études (EPHE), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), University of Southampton, and SNO-DYNALIT funded by Institut National des Sciences de l'Univers (INSU) of CNRS
Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Shore, geography, dune-beach interaction, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, shoreline prediction, time-scales, Sediment, 010502 geochemistry & geophysics, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, 01 natural sciences, Flattening, Geophysics, 13. Climate action, [SDE]Environmental Sciences, Erosion, 14. Life underwater, Physical geography, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, centroid Analysis, beach migration, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: Understanding the interactions between dune systems and beaches is critical to determining the short-term shoreline response and the long-term resilience. In this study, almost 15 years of monthly beach/dune measurements were analysed for three diﬀerent proﬁles at Vougot Beach, France to understand and predict shoreline changes from intra- to multi-annual time- scales. Four migration modes: advance/retreat (translation modes) and steepening/flattening (rotation modes) were identified through a centroid analysis. The analysis showed that translation and rotation can occur simultaneously, with long-term trends of beach retreat and profile steepening (lower beach retreating and upper beach advancing), which was interrupted by two energetic wave events causing profile ﬂattening (lower beach advancing and upper beach retreating). These two observations are evidence of how the sediment contribution resulting from the dune erosion events temporarily caused a large advance in the shoreline position. A recent modelling approach that accounts for diﬀerent time-scales is applied to predict the shoreline changes, showing signiﬁcant improvements in comparison to a traditional shoreline equilibrium model when time-scales related with the dune erosion and recovery are considered. The results showed that the dune system aﬀects the beach proﬁle evolution both spatially, with diﬀerent impacts at diﬀerent elevations along the cross-shore proﬁle, and temporally, by periodically redistributing the sediment in the system. Plain Language Summary Changes in the shoreline position are the result of a delicate balance between hydrodynamic (e.g., waves, currents, water levels) and morphology (e.g., dunes, beachface). Dunes are a natural barrier to storms and much of their ability to stand erosive events is related to their recovery after a storm. At the same time, the beachface often responds to incoming waves by either changing its slope (rotation mode) or by advancing/retreating (translation mode). Using 15 years of profile measurements at Vougot beach, France, we identified the different modes and observed if, when and how they occur. Our analysis shows that the evolution of the beach system was controlled by the sediment exchanges and redistribution between the dune and the intertidal beach. Different elevations of the intertidal beach profile showed distinct behaviour and different time-scales of change. Our work provides evidence that a multi-temporal scale approach is necessary to predict sediment redistribution along the beach profile.
Published: 2021
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28. Climate change impacts on coastal wave dynamics at Vougot Beach, France

Author: Pushpa Dissanayake, Marissa L. Yates, Serge Suanez, France Floc’h, Knut Krämer, Coastal Geology and Sedimentology, Institute of Geosciences (Université de Kiel), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Littoral, Environnement, Télédétection, Géomatique (LETG - Brest), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Caen Normandie (UNICAEN), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire Géosciences Océan (LGO), Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), SNO-DYNALIT funded by INSU of CNRS, Municipality of Guissény, MoDECS (Modification of Dune Erosion by adjacent Coastal Systems) project funded by German Research Foundation (DFG) under the grant number DI 2139/2-1, ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-Université de Nantes (UN)-École pratique des hautes études (EPHE), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Naval architecture. Shipbuilding. Marine engineering, Climate change, VM1-989, Ocean Engineering, GC1-1581, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, 14. Life underwater, wave impacts, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Coastal hazards, SWAN, macro-tidal coast, numerical modelling, Storm, Wave climate, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Sea level rise, 13. Climate action, Delft3D, Climatology, sea level rise, [SDE]Environmental Sciences, Environmental science, Spatial variability, Sediment transport
Abstract: Wave dynamics contribute significantly to coastal hazards and were thus investigated at Vougot Beach by simulating both historical and projected future waves considering climate change impacts. The historical period included a major storm event. This period was projected to the future using three globally averaged sea level rise (SLR) scenarios for 2100, and combined SLR and wave climate scenarios for A1B, A2, and B1 emissions paths of the IPCC. The B1 wave climate predicts an increase in the occurrence of storm events. The simulated waves in all scenarios showed larger relative changes at the beach than in the nearshore area. The maximum increase of wave energy for the combined SLR and wave scenarios was 95%, while only 50% for the SLR-only scenarios. The effective bed shear stress from waves and currents showed different spatial variability than that of the wave height, emphasizing the importance of interactions between nearshore waves and currents. Increases in the effective bed shear stress (combined scenarios: up to 190%, and SLR-only scenarios: 35%) indicate that the changes in waves and currents will likely have significant impacts on the nearshore sediment transport. This work emphasizes that combined SLR and future wave climate scenarios need to be used to evaluate future changes in local hydrodynamics and their impacts. These results provide preliminary insights into potential future wave dynamics at Vougot Beach under different climate change scenarios. Further studies are necessary to generalize the results by investigating the wave dynamics during storm events with different hydrodynamical conditions and to evaluate potential changes in sediment transport and morphological evolution due to climate change.
Published: 2021
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29. Experimental and numerical characterization of swell type waves effect on wind sea growth with fetch

Author: Villefer, Antoine, Benoit, Michel, Violeau, Damien, Teles, Maria, Jeffreys, Harris, Branger, Hubert, Luneau, Christopher, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Branger, Hubert, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.MECA.MEFL] Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2021

30. How to Quantify the Dynamics of Single (Straight or Sinuous) and Multiple (Anabranching) Channels from Imagery for River Restoration

Author: Arnaud-Fassetta, Gilles, Melun, Gabriel, Passy, Paul, Brousse, Guillaume, Theureaux, Olivier, Pôle de recherche pour l'organisation et la diffusion de l'information géographique (PRODIG (UMR_8586 / UMR_D_215 / UM_115)), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-AgroParisTech-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Office français de la biodiversité (OFB), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-AgroParisTech-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV)
Subjects: [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Technology, metric analysis grid, QH301-705.5, Physics, QC1-999, geomorphological monitoring, [SHS.GEO]Humanities and Social Sciences/Geography, Engineering (General). Civil engineering (General), Chemistry, fluvial geomorphology, geographic information system, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, TA1-2040, Biology (General), river restoration, QD1-999, river management
Abstract: Since the 2000s, European rivers have undergone restoration works to give them back a little more ‘freedom space’ and consolidate the hydro-sedimentary continuum and biological continuity as required by the Water Framework Directive (WFD). In high-energy rivers, suppression of lateral constraints (embankment removal) leads to geomorphological readjustments in the modification of both the active-channel length and active-channel width. The article provides a new methodological development to overcome the shortcomings of traditional methods (based on diachronic cross-section analysis) unable to simultaneously take into account these geometric adjustments after active-channel restoration. It allows us to follow and precisely quantify the geomorphological changes of the active channel faced to the stakes (i.e., structures or urbanized, recreation or agricultural areas) in the floodplain. The methodology proposes three new indicators (distance from active channel to stakes or floodplain margins as indicator 1, distance from stakes to active channel as indicator 2, diachronic distance as indicator 3) and a metric analysis grid in the 2D Euclidean space. It is applied to the Clamoux River (order 4, Strahler, bankfull, specific stream power: 280 W/m2) in the Aude watershed (Mediterranean France). The paper shows the full potential of this methodological protocol to be able to meet managers’ expectations as closely as possible within the framework of the multi-annual active-channel monitoring.
Published: 2021
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31. Influence of swell on wind-wave growth with fetch: an experimental and numerical study

Author: Villefer, Antoine, Teles, Maria, Benoit, Michel, Violeau, Damien, Harris, Jeffrey C., Branger, Hubert, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2021

32. Automatic Calibration of Bed Friction Coefficients to Reduce the Influence of Seasonal Variation: Case of the Gironde Estuary

Author: Fabrice Klein, Pablo Tassi, Sylvain Orseau, Nicolas Huybrechts, Hassan Smaoui, Centre de Recherche de Royallieu, Sorbonne Université (SU)-Université de Technologie de Compiègne (UTC), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Eau Mer et Fleuves (Cerema Direction Eau Mer et Fleuves), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: 010504 meteorology & atmospheric sciences, 0207 environmental engineering, Ocean Engineering, Soil science, 02 engineering and technology, Seasonality, medicine.disease, 01 natural sciences, 6. Clean water, Water level, Volumetric flow rate, Approximation error, [SDE]Environmental Sciences, Range (statistics), Calibration, medicine, Environmental science, 14. Life underwater, CMA-ES, 020701 environmental engineering, Evolution strategy, 0105 earth and related environmental sciences, Water Science and Technology, Civil and Structural Engineering
Abstract: International audience; An automatic procedure to identify the bed friction coefficient is tested on a 2D hydrodynamic model of the Gironde estuary (France). The proposed procedure involves an optimization algorithm based on evolution strategy, namely Covariance Matrix Adaptation Evolution Strategy. Without optimization, application of the same friction distribution to different hydrological conditions leads to significant relative error in water level prediction up to 20%–30%. For the tested configuration, 300 runs seemed to be sufficient to reach an optimal value whereas an additional 200 runs would help to gain an accuracy of a few millimeters (or 0.3%). In order to reach the same level of accuracy for the different hydrological configurations, it is necessary to adapt for each configuration of the bed friction coefficient. Such behavior tends to confirm a seasonal variation of the friction coefficient and this is particularly the case in the central part of the estuary. Different relationships of the friction coefficient according to the flowrate have been incorporated inside the 2D hydrodynamic model. These relationships effectively maintain an accurate prediction of the water levels close to 10% for a wide range of hydrological configurations.
Published: 2021
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33. Non-isothermal viscoelastic flows with conservation laws and relaxation

Author: Sébastien Boyaval, Mark Dostalík, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), MATHematics for MatERIALS (MATHERIALS), Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS), École des Ponts ParisTech (ENPC)-École des Ponts ParisTech (ENPC)-Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Charles University [Prague] (CU), Sébastien Boyaval has been supported by ANR JCJC SEDIFLOProject-ANR-15-CE01-0013.Mark Dostalık has been supported by the Czech Science Foundation, Grant Number 20-11027X. Additional funding was provided by institutional grants Charles University Grant Agency, Grant Number 1652119, and by Charles University Research Programme No. UNCE/SCI/023., Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS), and École des Ponts ParisTech (ENPC)-École des Ponts ParisTech (ENPC)
Subjects: Mathematics - Analysis of PDEs, General Mathematics, FOS: Mathematics, Balance laws, Short-time well-posedness, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Viscoelasticity, Maxwell fluid, Mathematical entropy, Analysis, Analysis of PDEs (math.AP)
Abstract: We propose a system of conservation laws with relaxation source terms (i.e. balance laws) for non-isothermal viscoelastic flows of Maxwell fluids. The system is an extension of the polyconvex elastodynamics of hyperelastic bodies using additional structure variables. It is obtained by writing the Helmholtz free energy as the sum of a volumetric energy density (function of the determinant of the deformation gradient det F and the temperature [Formula: see text] like the standard perfect-gas law or Noble–Abel stiffened-gas law) plus a polyconvex strain energy density function of F, [Formula: see text] and of symmetric positive-definite structure tensors that relax at a characteristic time scale. One feature of our model is that it unifies various ideal materials ranging from hyperelastic solids to perfect fluids, encompassing fluids with memory like Maxwell fluids. We establish a strictly convex mathematical entropy to show that the system is symmetric-hyperbolic. Another feature of the proposed model is therefore the short-time existence and uniqueness of smooth solutions, which define genuinely causal viscoelastic flows with waves propagating at finite speed. In heat-conductors, we complement the system by a Maxwell–Cattaneo equation for an energy-flux variable. The system is still symmetric-hyperbolic, and smooth evolutions with finite-speed waves remain well-defined.
Published: 2021

34. Submersions marines sur le littoral atlantique français : 700 ans d'archives sociétales et environnementales pour une meilleure connaissance et gestion du risque

Author: Mohamed Maanan, Emmanuelle Athimon, Pierre Pouzet, Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), École des Ponts ParisTech (ENPC), Observatoire des Sciences de l'Univers Nantes Atlantiques (OSUNA), Université d'Angers (UA)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Gustave Eiffel, Association de Géographes Français (AGF), Université d'Angers (UA)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université (HESAM)-HESAM Université (HESAM)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Pouzet, Pierre
Subjects: Résilience sociétale, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SHS.GEO] Humanities and Social Sciences/Geography, Sédimentologie, [SDE.MCG]Environmental Sciences/Global Changes, Geography, Planning and Development, [SHS.GEO]Humanities and Social Sciences/Geography, Aménagement du territoire, [SDE.ES]Environmental Sciences/Environmental and Society, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, Submersion marine, [SDE.MCG] Environmental Sciences/Global Changes, Tempête, Risques côtiers, [SDE.ES] Environmental Sciences/Environmental and Society, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Archives historiques, Earth-Surface Processes
Abstract: National audience; Cette recherche, financée par la Fondation de France, avait pour objectifs : 1) de retracer l’histoire des submersions marines dans l’ouest de la France à l’aide d’approches pluridisciplinaires, 2) d’évaluer les impacts quantitatifs de ces évènements sur les sociétés littorales et 3) de définir la notion de « résilience sociétale » sous le prisme historique. La méthodologie repose sur une approche interdisciplinaire intégrant la sédimentologie (21 carottes sédimentaires ont été prélevées) et l’histoire du climat (19 888 documents historiques ont été dépouillés et analysés). Le cadre spatiotemporel de l'étude est localisé au niveau de la façade atlantique française, de la Petite mer de Gâvres à l'île de Ré, et couvrant une période allant du XIVe siècle à nos jours. Le couplage des données sédimentologiques avec les archives historiques a permis de caractériser seize évènements extrêmes à forts impacts environnementaux et sociétaux. L’un d’entre eux, survenu durant l’hiver 1351 – 1352 (n.st) AD, est qualifié d’« évènement millénaire ». Les résultats de cette recherche témoignent de l’adaptabilité des populations et de leur tolérance au risque de submersion marine à travers l’histoire. À travers cette lecture historique, ces différentes approches permettent d’accroître la connaissance des aléas côtiers, de contribuer à leur prévention et de proposer des outils prospectifs pour la gestion des risques côtiers.
Published: 2021

35. Physically interpretable machine learning algorithm on multidimensional non-linear fields

Author: Cédric Goeury, Pablo Tassi, Fabrice Zaoui, Rem-Sophia Mouradi, Olivier Thual, EDF R&D (EDF R&D), EDF (EDF), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF (EDF)-EDF (EDF), Climat, Environnement, Couplages et Incertitudes [Toulouse] (CECI), CERFACS-Centre National de la Recherche Scientifique (CNRS), Institut de mécanique des fluides de Toulouse (IMFT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), CECI, CERFACS / CNRS (CECI), Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique - CNRS (FRANCE), EDF (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Centre d'études et d'expertise sur les risques, l'environnement, la mobilité et l'aménagement - CEREMA (FRANCE), Centre Européen de Recherche et Formation Avancées en Calcul Scientifique - CERFACS (FRANCE), Ecole des Ponts ParisTech (FRANCE), and MOURADI, Rem-Sophia
Subjects: [SDE] Environmental Sciences, FOS: Computer and information sciences, Computer Science - Machine Learning, Physics and Astronomy (miscellaneous), Computer science, Mécanique des fluides, 010103 numerical & computational mathematics, computer.software_genre, 01 natural sciences, Field (computer science), Machine Learning (cs.LG), [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], [SPI]Engineering Sciences [physics], [STAT.ML]Statistics [stat]/Machine Learning [stat.ML], Statistics - Machine Learning, Numerical Analysis, [STAT.ME] Statistics [stat]/Methodology [stat.ME], Polynomial chaos, Applied Mathematics, Machine Learning (ML), Computational Physics (physics.comp-ph), Computer Science Applications, 010101 applied mathematics, Computational Mathematics, Modeling and Simulation, [SDE]Environmental Sciences, Pattern recognition (psychology), Physics - Computational Physics, [STAT.ME]Statistics [stat]/Methodology [stat.ME], Data compression, [SPI] Engineering Sciences [physics], FOS: Physical sciences, Context (language use), Machine Learning (stat.ML), Machine learning, Methodology (stat.ME), Geoscieces, Data-Driven Model (DDM), 0101 mathematics, Uncertainty quantification, Statistics - Methodology, Polynomial Chaos Expansion (PCE), business.industry, Dimensionality reduction, [STAT.ML] Statistics [stat]/Machine Learning [stat.ML], Proper Orthogonal Decomposition (POD), Physics - Data Analysis, Statistics and Probability, Data quality, Dimensionality Reduction (DM), Artificial intelligence, business, computer, Data Analysis, Statistics and Probability (physics.data-an)
Abstract: International audience; In an ever-increasing interest for Machine Learning (ML) and a favorable data development context, we here propose an original methodology for data-based prediction of two-dimensional physical fields. Polynomial Chaos Expansion (PCE), widely used in the Uncertainty Quantification community (UQ), has long been employed as a robust representation for probabilistic input-to-output mapping. It has been recently tested in a pure ML context, and shown to be as powerful as classical ML techniques for point-wise prediction. Some advantages are inherent to the method, such as its explicitness and adaptability to small training sets, in addition to the associated probabilistic framework. Simultaneously, Dimensionality Reduction (DR) techniques are increasingly used for pattern recognition and data compression and have gained interest due to improved data quality. In this study, the interest of Proper Orthogonal Decomposition (POD) for the construction of a statistical predictive model is demonstrated. Both POD and PCE have amply proved their worth in their respective frameworks. The goal of the present paper was to combine them for a field-measurement-based forecasting. The described steps are also useful to analyze the data. Some challenging issues encountered when using multidimensional field measurements are addressed, for example when dealing with few data. The POD-PCE coupling methodology is presented, with particular focus on input data characteristics and training-set choice. A simple methodology for evaluating the importance of each physical parameter is proposed for the PCE model and extended to the POD-PCE coupling.
Published: 2021
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36. NavTEL: an open-source tool for ship routing and underkeel clearance management in estuarine channels

Author: Orseau, Sylvain, Huybrechts, Nicolas, Tassi, Pablo, Kaidi, Sami, Klein, Fabrice, Centre de Recherche de Royallieu, Sorbonne Université (SU)-Université de Technologie de Compiègne (UTC), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), and Grand Port Maritime de Bordeaux
Subjects: [PHYS]Physics [physics]
Abstract: International audience; NavTEL is a new decision support tool for the short-term (36 h) planning of ship routes and the management of underkeel clearance in estuarine navigation channels. NavTEL uses a deterministic method and is coupled with the TELEMAC-MASCARET system for numerical modeling of hydrodynamic and sediment transport in the estuary with a two-dimensional approach. In its present version, NavTEL allows (i) daily simulations to be automatically prepared and launched; and (ii) simulation outputs to be postprocessed to find the safest ship route and to predict underkeel clearances at specified locations. As the reliability of the results relies on the accuracy of water-level predictions, numerical simulations were performed with measured river discharges, storm surge forecasts, and time-varying friction coefficients for bed roughness. Even though NavTEL was initially developed for the Atlantic Port of Bordeaux located in the Gironde Estuary, its kernel has a modular structure allowing the tool to be adjusted to different port configurations and types of water bodies. Finally, examples of graphical outputs and reports generated by NavTEL are shown for an application of a container ship coming into the port of Bordeaux.
Published: 2021
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37. Experimental flows through an array of emerged or slightly submerged square cylinders over a rough bed

Author: Frédérique Larrarte, Sébastien Proust, Nicole Goutal, Marina Oukacine, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Riverly (Riverly), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and ANR-14-CE03-0010,FLOWRES,Prédire les écoulements dans les plaines d'inondation dont l'occupation du sol varie, lors de crues extrêmes(2014)
Subjects: Statistics and Probability, Data Descriptor, 010504 meteorology & atmospheric sciences, Floodplain, Science, 0208 environmental biotechnology, Flow (psychology), Soil science, 02 engineering and technology, Library and Information Sciences, 01 natural sciences, Cylinder (engine), law.invention, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], Education, Fluid dynamics, law, Acoustic Doppler velocimetry, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Flood myth, Natural hazards, 6. Clean water, 020801 environmental engineering, Computer Science Applications, Flume, Particle image velocimetry, Statistics, Probability and Uncertainty, Geology, Information Systems
Abstract: The experimental dataset presented was collected in an 18 m long and 1 m wide laboratory flume. Low to high flood flows through an urbanized floodplain were modelled. The floodplain bed is rough, modelled with dense artificial grass. A square cylinder array, representing house models, was set on the rough bed. The cylinder immersion rate was varied: cylinders are emerged for three flow cases and slightly submerged for one case. The experimental dataset comprises water levels, measured using an ultrasonic transit time probe, velocities across the channel measured using an Acoustic Doppler Velocimetry with a side looking probe, and velocities in longitudinal-vertical planes measured using Particle Image Velocimetry. These data could help understanding the physical processes associated with high flood flows through urbanized floodplains, with a focus on the transition from emerged to submerged obstacles. They could also be used as benchmark data to assess the ability of numerical models from one to three-dimensions to estimate the flood hazard (water depth, velocity) over a wide range of flood event magnitudes., Measurement(s) velocity • depth of water Technology Type(s) particle-image velocimetry • ultrasonic velocimetry • ultrasonic transit time probe Factor Type(s) square cylinder immersion rate Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.13286915
Published: 2021
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38. Finite-Volume approximation of the invariant measure of a viscous stochastic scalar conservation law

Author: Boyaval, Sébastien, Martel, Sofiane, Reygner, Julien, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), MATHematics for MatERIALS (MATHERIALS), Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS), École des Ponts ParisTech (ENPC)-École des Ponts ParisTech (ENPC)-Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), SIMulation pARTiculaire de Modèles Stochastiques (SIMSMART), Institut de Recherche Mathématique de Rennes (IRMAR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Inria Rennes – Bretagne Atlantique, École des Ponts ParisTech (ENPC), This work is partially supported by the French National Research Agency (ANR) under the programs ANR-19-CE40-0010 (QuAMProcs)and ANR-17-CE40-0030 (EFI)., ANR-17-CE40-0030,EFI,Entropie, flots, inégalités(2017), and ANR-19-CE40-0010,QuAMProcs,Analyse Quantitative de Processus Metastables(2019)
Subjects: [MATH.MATH-PR]Mathematics [math]/Probability [math.PR], Finite Volume schemes, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], Invariant measure, Stochastic conservation laws, 2010 Mathematics Subject Classification : 60H15,30R60,65M08,60H35
Abstract: We study the numerical approximation of the invariant measure of a viscous scalar conservation law, one-dimensional and periodic in the space variable, and stochastically forced with a white-in-time but spatially correlated noise. The flux function is assumed to be locally Lipschitz continuous and to have at most polynomial growth. The numerical scheme we employ discretises the SPDE according to a finite-volume method in space, and a split-step backward Euler method in time. As a first result, we prove the well-posedness as well as the existence and uniqueness of an invariant measure for both the semi-discrete and the split-step scheme. Our main result is then the convergence of the invariant measures of the discrete approximations, as the space and time steps go to zero, towards the invariant measure of the SPDE, with respect to the second-order Wasserstein distance. We investigate rates of convergence theoretically, in the case where the flux function is globally Lipschitz continuous with a small Lipschitz constant, and numerically for the Burgers equation.
Published: 2021

39. Géohistoire des tempêtes et submersions marines depuis 1 000 ans : quelles interprétations climatiques dans l’ouest de la France ?

Author: Pouzet, Pierre, Athimon, Emmanuelle, Maanan, Mohamed, Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Nantes (UN)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: sources historiques, climatologie, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Atlantic coast, [SDE.MCG]Environmental Sciences/Global Changes, historical sources, sedimentology, climatology, [SHS.GEO]Humanities and Social Sciences/Geography, sédimentologie, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, côte atlantique
Abstract: International audience; In the current climate change context, studying coastal risks involves considering the hazard’s historical fluctuations to understand the ocean-climatic parameters that guide its variability. Thanks to the coupling of sedimentological and historical data, fifteen intense storms were extracted from a core sampled in the Traicts of the Croisic, while 128 impacting events were recorded by historical sources during the last millennium. The synthesis of sedimentological and historical works carried out in western France highlights three common stormy periods estimated at approximately 1330 – 1360 AD, 1570 – 1620 AD and 1690 – 1720 AD. These three periods are part of climate pejoration phases, or of cold tendencies. While storm activity appears to increase during North Atlantic Oscillation (NAO)’s positive phases, no strict correlations are established. The change in position of the “mid-latitude storm tracks” could also explain some trajectories. To put these results into perspective and offer new prospects to improve French coastal risk management, the limits of this study are also discussed. This approach must be more exhaustive to specify the tempestuous chronology, but also extend it to the entire French Atlantic coast and thus consider all the mechanisms likely to guide their formation in Western Europe; Dans le contexte actuel lié au changement climatique, l’étude des risques côtiers implique la considération des fluctuations historiques de l’aléa pour comprendre les paramètres océano-climatiques guidant sa variabilité. Grâce au couplage entre données sédimentologiques et historiques, quinze tempêtes intenses ont été extraites d’un carottage prélevé aux Traicts du Croisic, tandis que 128 évènements impactant ont été recensés par les sources historiques durant le dernier millénaire. La synthèse des travaux sédimentologiques et historiques réalisée dans l’ouest de la France met en lumière trois périodes tempétueuses communes estimées à environ 1330 – 1360 ap. J.-C., 1570 – 1620 ap. J.-C. et 1690 – 1720 ap. J.-C. Ces trois périodes s’inscrivent durant des phases de péjoration climatique, ou de tendance froide. Si l’activité tempétueuse semble être accrue durant les phases positives d’Oscillation Nord Atlantique (ONA), aucune corrélation stricte n’est établie. La variation de position du “rail des dépressions” expliquerait également certaines trajectoires. Pour relativiser ces résultats et proposer de nouvelles perspectives pour améliorer la gestion des risques côtiers en France, les limites de cette étude sont également discutées. Cette approche doit notamment gagner en exhaustivité pour préciser la chronologie tempétueuse, mais également l’étendre sur la totalité de la façade atlantique française et ainsi considérer l’ensemble des mécanismes susceptibles de guider leur formation en Europe de l’Ouest.
Published: 2021
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40. Subaquatic Relaxed Eddy Accumulation: A new technique to resolve benthic solute fluxes

Author: Calabro Souza, Guilherme, DUBOIS, Philippe, Saad, Mohamed, Lorke, Andreas, Noss, Christian, Boudahmane, Lila, lauret, olivier, Brigitte, VInçon-Leite, Jodeau, Magali, Moilleron, Régis, Lemaire, Bruno J., Lemaire, Bruno J., Laboratoire Eau Environnement et Systèmes Urbains (LEESU), École des Ponts ParisTech (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Universität Koblenz-Landau [Koblenz], Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Hydrosystèmes continentaux anthropisés : ressources, risques, restauration (UR HYCAR), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), AgroParisTech, AquaREA, and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: Turbulence, [SDE] Environmental Sciences, [SDE]Environmental Sciences, Hydrodynamics, Biogeochemistry, Instrumentation
Abstract: International audience; The transport across the sediment-water interface of solutes, dissolved oxygen, nutrients and contaminants is of major importance for biogeochemical cycles and water quality in aquatic ecosystems. This exchange depends not only on biogeochemical processes and on temperature, but also strongly on near-bed currents. Eddy covariance measurements in a lake showed that oxygen benthic fluxes can vary over minutes to hours. However, the corresponding dynamics of nutrient and contaminant fluxes is still not fully understood. Common techniques fail to capture the turbulence-driven fluxes of interfacial transport for most chemical species, particularly in situ and at high temporal resolution. At the land-atmosphere interface, this issue is addressed with the relaxed eddy accumulation (REA), a conditional sampling technique. Samples are accumulated at constant flow rate in separated containers depending on the direction of the vertical flow. The vertical flux is finally assumed to be proportional to the concentration difference of sample pairs, which might be analysed in situ or at lab.The adaptation of the technique for measuring fluxes through the sediment-water interface is presented here. A portable prototype was developed, embedding both relaxed eddy accumulation and eddy covariance as a reference technique for validation. Vertical Dissolved oxygen fluxes were measured during ca. 10 min accumulation periods, at ca. 15 cm above the sediment, in spring and summer and at different sites: a laboratory flume with an artificial oxygen flux, a river branch, a creek, a shallow lake and an experimental lake. Oxygen fluxes measured with both techniques showed a good agreement, which validates both the technique and the prototype. The new device proves to be a promising tool to access benthic fluxes at high frequency over a flat sediment-water interface. First time series of nutrient fluxes will be presented.
Published: 2021

41. Hydrodynamic modelling for early warning of sanitary risks in open swimming waters

Author: Angelotti, Natalia, Vinçon-Leite, Brigitte, Carmigniani, Rémi, TELEMAC-MASCARET Core Group, Angelotti de Ponte Rodrigues, Natalia, Laboratoire Eau Environnement et Systèmes Urbains (LEESU), École des Ponts ParisTech (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: [SDV.EE.SANT]Life Sciences [q-bio]/Ecology, environment/Health, [SDE.IE]Environmental Sciences/Environmental Engineering, [SDV.EE.SANT] Life Sciences [q-bio]/Ecology, environment/Health, Hydrodynamik (532.5), [SDE.IE] Environmental Sciences/Environmental Engineering
Abstract: International audience; Swimming in open water involves sanitary risks related to the presence of pathogenic microorganisms. To ensure the safety of bathers, a regulatory monitoring in the bathing area, based on faecal indicator bacteria (FIB), is required. Analysis of FIB concentrations can take more than 10 hours with in situ devices and more than 24 hours in the laboratory. Hence monitoring and forecasting of the sanitary conditions in urban bathing sites are essential for decision-making on their possible closure and its duration. In this paper, TELEMAC-3D hydrodynamic model was used to compute the time and space distribution of water temperature, velocity and contaminant tracers considering hydrometeorological conditions that can cause noticeable changes on the transfer time of the contaminant to the bathing area. The study site, La Villette, is an urban canal-basin system with a bathing area, located in Paris. The objectives focus on (i) how thermal stratification affects the transfer time of upstream contamination to the bathing area; (ii) the use of conductivity to track water quality changes after a storm event and (iii) the simulation of conductivity variation.
Published: 2021

42. A well-defined moving steady states capturing Godunov-type scheme for Shallow-water model

Author: Berthon, Christophe, M'Baye, Meissa, Le, Minh, Seck, Diaraf, Laboratoire de Mathématiques Jean Leray (LMJL), Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS), Mathématiques - Analyse, Probabilités, Modélisation - Orléans (MAPMO), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mathématique de la Décision et d'Analyse Numérique (L.M.D.A.N), Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD), Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: Fully Wellbalanced schemes, Hyperbolic conservation laws, Godunov-type schemes, Balance laws, entropy inequalities, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA]
Abstract: International audience; The present work concerns the derivation of a well-balanced scheme to approximate the weak solutions of the shallow-water model. Here, the numerical scheme exactly captures all the smooth steady solutions with nonvanishing velocities. To address such an issue, a Godunov-type scheme is adopted. A particular attention is paid on the derivation of the intermediate states within the approximate Riemann solver. Indeed, because of the moving steady states, the intermediate states may be ill-defined. Here, we introduce a suitable correction in order to get a fully well-defined finite volume scheme. In addition, the numerical method is established to be positive preserving and to satisfy a discrete entropy inequality up to small perturbations. Several numerical experiments, including wet/dry transition, illustrate the relevance of the designed scheme.
Published: 2021

43. Influence of following, regular and irregular long waves on wind-wave growth with fetch: an experimental study

Author: Michel Benoit, Damien Violeau, Antoine Villefer, Christopher Luneau, Hubert Branger, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), and Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, Fetch, Oceanography, 01 natural sciences, 010305 fluids & plasmas, 0103 physical sciences, Wind wave, Kondratiev wave, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Seismology, Geology, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: A series of experiments were conducted in a wind-wave tank facility in Marseilles (France) to study the effects of preexisting swell conditions (represented by long mechanically-generated waves) on wind-wave growth with fetch. Both monochromatic and irregular (JONSWAP-type) long wave conditions with different values of wave steepness have been generated in the presence of a constant wind forcing, for several wind velocities. A spectral analysis of temporal wave signals combined with airflow measurements allowed to study the evolution of both wave systems with the aim of identifying the interaction mechanisms transportable to prototype scale. In particular, a specific method is used to separate the two wave systems in the measured bimodal spectra. In fetch-limited conditions, pure wind-wave growth is in accordance with anterior experiments, but differs from the prototype scale in terms of energy and frequency variations with fetch. Monochromatic long waves are shown to reduce the energy of the wind-waves significantly, as it was observed in anterior laboratory experiments. The addition of JONSWAP-type long waves instead results in a downshift of the wind-wave peak frequency but no significant energy reduction. Overall, it is observed that the presence of long waves affects the wind-wave energy and frequency variations with fetch. Finally, in the presence of JONSWAP-type long waves, variations of wind-wave energy and peak frequency with fetch appear in close agreement with the wind-wave growth observed at prototype scale both in terms of variations and nondimensional magnitude.
Published: 2021
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44. Projection du film 'Le risque de submersion, une forte vulnérabilité régionale : de la recherche scientifique à la gestion des risques'

Author: Pouzet, Pierre, Athimon, Emmanuelle, Observatoire des Sciences de l'Univers Nantes Atlantique (OSUNA), Université d'Angers (UA)-Université de Nantes (UN)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université (HESAM)-HESAM Université (HESAM)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), École des Ponts ParisTech (ENPC), and Université d'Angers (UA)-Université de Nantes (UN)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Sédimentologie, Dendrochronologie, Xynthia, [SDE.MCG]Environmental Sciences/Global Changes, [SHS.GEO]Humanities and Social Sciences/Geography, Aménagement du territoire, [SDE.ES]Environmental Sciences/Environmental and Society, Submersion marine, Tempête, Risques côtiers, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, Archives historiques
Abstract: International audience
Published: 2020

45. Viscoelastic flows of Maxwell fluids with conservation laws

Author: Sébastien Boyaval, MATHematics for MatERIALS (MATHERIALS), Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS), École des Ponts ParisTech (ENPC)-École des Ponts ParisTech (ENPC), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), ANR-15-CE01-0013,SEDIFLO,Modélisation et simulation du transport solide en rivières(2015), Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS), École des Ponts ParisTech (ENPC)-École des Ponts ParisTech (ENPC)-Inria de Paris, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), and Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (LHSV)
Subjects: FOS: Physical sciences, 01 natural sciences, Viscoelasticity, 010305 fluids & plasmas, Causality (physics), Physics::Fluid Dynamics, Mathematics - Analysis of PDEs, [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], 0103 physical sciences, Maxwell fluids, FOS: Mathematics, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Viscoelastic flows, 0101 mathematics, Mathematical Physics, Conservation laws, Variable (mathematics), Mathematics, Numerical Analysis, Conservation law, Symmetric-hyperbolic systems, Computer Science::Information Retrieval, Applied Mathematics, Mathematical analysis, Relaxation (iterative method), Mathematical Physics (math-ph), [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph], 010101 applied mathematics, Computational Mathematics, Cover (topology), Modeling and Simulation, Metric (mathematics), Compressibility, Analysis, Analysis of PDEs (math.AP)
Abstract: We consider multi-dimensional extensions of Maxwell’s seminal rheological equation for 1D viscoelastic flows. We aim at a causal model for compressible flows, defined by semi-group solutions given initial conditions, and such that perturbations propagate at finite speed. We propose a symmetric hyperbolic system of conservation laws that contains the Upper-Convected Maxwell (UCM) equation as causal model. The system is an extension of polyconvex elastodynamics, with an additional material metric variable that relaxes to model viscous effects. Interestingly, the framework could also cover other rheological equations, depending on the chosen relaxation limit for the material metric variable. We propose to apply the new system to incompressible free-surface gravity flows in the shallow-water regime, when causality is important. The system reduces to a viscoelastic extension of Saint-Venant 2D shallow-water system that is symmetric-hyperbolic and that encompasses our previous viscoelastic extensions of Saint-Venant proposed with F. Bouchut.
Published: 2020
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46. Large Eddy Simulation for flows through emerged or slightly sub-merged square obstacles

Author: Oukacine, Marina, Rtimi, Rajae, Goutal, Nicole, Larrarte, Frédérique, Loizeau, Vincent, Benhamadouche, Sofiane, Proust, Sébastien, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Sols, Roches et Ouvrages Géotechniques (GERS-SRO), Université Gustave Eiffel, Performance, Risque Industriel, Surveillance pour la Maintenance et l’Exploitation (EDF R&D PRISME), EDF R&D (EDF R&D), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Cadic, Ifsttar
Subjects: HYDRAULICS, OBSTACLE, EXPERIMENTS, SIMULATION, [SDU.STU.HY] Sciences of the Universe [physics]/Earth Sciences/Hydrology, FLOOD, HYDRAULIQUE, MODELISATION NUMERIQUE, CRUE, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, CFD
Abstract: River Flow 2020 -10th Conference on Fluvial Hydraulics, DELFT, PAYS-BAS, 07-/07/2020 - 10/07/2020; As a result of climate change, we believe that extreme floods will become more frequent and more intense. The flows through obstacles representing an urbanized floodplain is realised in a laboratory at Re = 4766 and 8580. The purpose of the present study is first to validate a numerical model using Large Eddy Simulation (LES) against experimental data regarding the average longitudinal velocity and the secondary vortices formation. Then, additional data can be obtained and quantified. Therefore the geometrical parameters can be changed and their influence analysed and compared to the literature. A good agreement was found between simulated and experimental vertical profiles of time averaged velocity for the flow through emerged or slightly submerged obstacles. The additional simulations highlight that the flow structure is mostly driven by the transverse aspect ratio using the distance between two adjacent obstacles.
Published: 2020

47. A new criterion for the evaluation of the velocity field for rainfall-runoff modelling using a shallow-water model

Author: Germain Antoine, Olivier Delestre, Florent Taccone, Nicole Goutal, Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), LJAD, Laboratoire Jean Alexandre Dieudonné (JAD), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Watershed, 010504 meteorology & atmospheric sciences, [SDE.IE]Environmental Sciences/Environmental Engineering, 0208 environmental biotechnology, Soil science, Hydrograph, 02 engineering and technology, 01 natural sciences, 6. Clean water, 020801 environmental engineering, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], Waves and shallow water, Infiltration (hydrology), Test case, 13. Climate action, Vector field, Surface runoff, Shallow water equations, Geology, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], 0105 earth and related environmental sciences, Water Science and Technology
Abstract: International audience; The aim of this work is to evaluate the accuracy of physically based models using the 2D Shallow Water Equations (SWE) for the simulation of rain-induced runoff. A key expectation of these models is to be able to reproduce properly both hydrograph at the outlet of the watershed and the associated velocity field within the spatial domain for a given rain event. However, this ability can be very challenging in mountainous environments, which include heterogeneous and high values of bottom slope and transient rain inputs. In this paper, we focused on both the error due to the numerical resolution of the SWE for low water depths runoff on steep slopes and that due to the physical representation of friction on the bottom for various water depth to roughness height ratios. Four test cases have been used, at different scales, to evaluate the model in comparison with experimental data. The first test case (from [Kirstetter et al., 2015]) was a rain induced flow in a straight channel. It allows to evaluate the error made for the chosen numerical resolution of the SWE and its impact on the velocity distribution in the domain (metric scale). A criterion defining an acceptable numerical error has been proposed. A second test case (from [Cea et al., 2014]), has been chosen for being also metric scaled and in the right range of the numerical error criterion. It allowed to evaluate the ability of a new friction law (adapted from [Lawrence, 1997]) to represent the measured velocity field in several inundation regimes at the metric scale. The third test case was a 40 m 2 real plot studied by [Tatard et al., 2008]. On this test case, measured velocities have been compared with the simulated ones. Thanks to an infiltration source term added to the mass conservation equation, hydrographs at the outlet of the plot have been well reproduced, as well as the main part (including the highest values) of the measured velocities. In particular, the velocities are well represented when the criterion given in the first test case is satisfied. Finally, the model is applied to a real watershed with an area of 1 km 2 on which hydrographs at the outlet have been successfully reproduced for two extreme rainy events [Le Bouteiller et al., 2015]. It appeared that both physical and numerical error were low in the hydrographic network and that the local velocities are correctly reproduced there, unlike in the hillslopes where the velocities are not well reproduced even if the mass fluxes are correct.
Published: 2020
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48. Energy Transfers and Reflection of Infragravity Waves at a Dissipative Beach Under Storm Waves

Author: Thomas Guérin, Anouk de Bakker, Olivier de Viron, Xavier Bertin, Thibault Coulombier, Kévin Martins, Teddy Chataigner, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Deltares system, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
Subjects: Shore, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Infragravity wave, Storm, Geophysics, Dissipation, Surf zone, Oceanography, 01 natural sciences, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Reflection (physics), Dissipative system, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Geology, 0105 earth and related environmental sciences, Envelope (waves)
Abstract: International audience; This study presents unpublished field observations of infragravity waves, collected at the dissipative beach of Saint‐Trojan (Oléron Island, France) during the storm Kurt (3 February 2017), characterized by incident short waves of significant heights reaching 9.5 m and peak periods reaching 22 s. Data analysis reveals the development of exceptionally large infragravity waves, with significant heights reaching 1.85 m close to shore. Field observations are complemented by numerical modeling with XBeach, which well reproduces the development of such infragravity waves. Model results reveal that infragravity waves were generated mainly through the bound wave mechanism, enhanced by the development of a phase lag with the shortwave energy envelope. Spectral analysis of the free surface elevation shows the generation of superharmonic and subharmonic infragravity waves, the latter dominating the free surface elevation variance close to shore. Modeling results suggest that subharmonic infragravity waves result, at least partly, from infragravity‐wave merging, promoted by the combination of free and bound infragravity waves propagating across a several kilometer‐wide surf zone. Due to the steeper slope of the upper part of the beach profile, observed and modeled reflection coefficients under moderate‐energy show a strong tidal modulation, with a weak reflection at low tide (R2
Published: 2020
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49. Societies Facing Hydrological Extremes: The Case of Urban Supplies in France (Middle Ages to End of the Eighteenth Century)

Author: Metzger, Alexis, Athimon, Emmanuelle, Litzenburger, Laurent, Giacona, Florie, Desarthe, Jérémy, Institut de Géographie - Lausanne (IGUL), Université de Lausanne (UNIL), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Centre de Recherche Universitaire Lorrain d'Histoire (CRULH), Université de Lorraine (UL), Erosion torrentielle neige et avalanches (UR ETGR (ETNA)), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Histoire, Territoires & Mémoires (HisTeMé ), Université de Caen Normandie (UNICAEN), and Normandie Université (NU)-Normandie Université (NU)
Subjects: History, Moyen Age, 010504 meteorology & atmospheric sciences, [SDE]Environmental Sciences, Climat -- Changements, Agriculture, Epoque moderne et contemporaine, 010501 environmental sciences, [SHS.HIST]Humanities and Social Sciences/History, 01 natural sciences, 0105 earth and related environmental sciences, Food Science
Abstract: International audience; This article aims to study a relatively overlooked subject: extreme hydrometeorological events, their effects on urban supplies of primary commodities, and the ways in which urban societies used to deal with them. The analysis focuses on French cities and spans a period from the Middle Ages to late eighteenth century. It studies the reactions of urban societies to supply issues, due to either hydrological excesses or deficits provoked by floods or droughts. The analysis shows that populations and urban authorities developed different kinds of adaptive strategies, especially to further social stability.; Cet article s’intéresse aux événements hydrométéorologiques extrêmes sous l’angle jusqu’ici peu étudié de l’approvisionnement urbain des sociétés qui ont à y faire face. L’analyse se concentre sur des villes françaises du Moyen Âge à la fin du XVIIIe siècle. L’article montre les réactions des sociétés urbaines lors de problèmes d’approvisionnement en raison d’excès ou de déficits hydrologiques. De ce fait, il souligne que les aléas hydrométéorologiques extrêmes ont pu entraîner des soucis d’approvisionnement des villes (alimentaire, en sel, en bois, etc.), conduisant à des formes d’adaptation par les populations et les autorités urbaines au nom, notamment, de la stabilité sociale.
Published: 2019
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50. Optimal sponge layer for water waves numerical models

Author: Remi Carmigniani, Damien Violeau, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Laboratoire National d’Hydraulique et Environnement (EDF R&D LNHE), and EDF R&D (EDF R&D)
Subjects: Environmental Engineering, Materials science, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Mechanics of the fluids [physics.class-ph], 010504 meteorology & atmospheric sciences, Linear system, Mathematical analysis, Linear model, Boundary (topology), Ocean Engineering, Solver, Dissipation, System of linear equations, 01 natural sciences, Finite element method, 010305 fluids & plasmas, 0103 physical sciences, Reflection coefficient, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: We present the system of linear equations to be solved to evaluate the reflection coefficient at a sponge layer boundary with damping forces ρ f S L = − ρ β u , where β is the sponge layer function. The case of 2D waves is discussed in details and different sponge layer functions are proposed. The linear system is solved using the finite element method (FEM) at low computational cost compared to the target simulations. This method should enable the design of efficient sponge layer for any full Navier–Stokes solvers. The linear model results solved with a FEM solver are compared here to SPH simulations with good agreement. The linear model is then used to determine the reflection coefficient for different power sponge functions, length and dissipation coefficient using the FEM solver. The linear model solved by a simple FEM solver can be used to evaluate the suitable dissipation coefficients for waves ranging from shallow to deep water for a given sponge layer length. The coefficient depends on the non-dimensional frequency for Ω = ω d / g 2 . A table of suitable parameters for different sponge layer functions is provided over a large range of non-dimensional frequency and sponge layer length. A 3D application of waves is also presented with 45° incidence angle.
Published: 2018
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