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The study presented in the present paper deals with the modeling of the rotation effects on a homogeneous turbulence evolving without a mean velocity gradient. The developed model results from a modification of the second order model of Haworth and Pope. This modification is expressed as a function of the rotation rate, of the component of the Reynolds tensor and of the characteristic length scale in the direction of the rotation axis. The obtained results have evidenced the great capacity of the present model to describe the rotation effects on the time evolution of the homogeneous decaying turbulence. [ABSTRACT FROM AUTHOR]

Some elements are given on the very multiform career of Antoine Craya. In addition to a strong involvement in applied hydraulics in Grenoble, he was very influential on the research of his colleagues: to give only a few examples of well-known scientists in the Lyon–Grenoble area, he inspired the doctoral work on wall-jets by Jean Mathieu, the doctoral work on channel flow by Geneviève Comte-Bellot, and the dominant research area of René Moreau on magnetohydrodynamic (MHD) turbulence. The main part of this article is devoted to the legacy of Antoine Craya, from his own doctoral dissertation (1957). Inspired by G.I. Taylor probably more than by G. Batchelor, he contributed to establish the concept of HAT (Homogeneous Anisotropic Turbulence), as a useful intermediate step between HIT (Homogeneous Isotropic Turbulence) and fully statistically inhomogeneous turbulent flows. For this purpose, a mean flow with space-uniform velocity gradient can inject energy and anisotropy to a fluctuating flow, and statistical homogeneity is restricted to fluctuations. Complete equations for two-point second-order and three-point third-order velocity correlations were written, both in physical space and in Fourier space, in order to exactly solve mixed pressure–velocity correlations thanks to the incompressibility constraint. Antoine Craya is well known for the use of the eponymous frame of reference, thanks to Jacks Herring (1974). Later recognized as a spectral counterpart of a general decomposition in terms of toroidal/poloidal/dilatational modes, this frame leads to expressing the spectral tensors of correlation with a minimal number of scalar (or pseudo-scalar) descriptors, without loss of information and for arbitrary anisotropy. Craya provided us with a special angle of attack of the so-called RDT (Rapid Distortion Theory) and triadic closures, even if he did not work directly on them. Accordingly, this paper is also an opportunity to come back on the long history of RDT, including the Spectral Linear Theory as a better nomenclature, especially for recent studies. As far as possible, historical milestones are recalled throughout this article, and one recovers the Lagrangian formalism of Cauchy, emphasized by Uriel Frisch as well, with the use of a ‘Cauchy matrix’ in connection with linear theory. Finally, it is shown how the legacy of Craya is present in new (not addressed by him) domains, such as stratified turbulence and MHD turbulence. We discuss how further (past 1957) approaches, by Keith Moffatt (spectral linear theory, 1967), and Steven Orszag (triadic closure for HIT, as EDQNM, Eddy Damped Quasi-Normal Approximation, 1970) can be integrated in a general approach to anisotropic turbulence, which still benefits from Craya's legacy. A synoptic scheme for the description of multipoint statistics is re-discussed on this occasion. More incidentally, connections with Kraichnan theories and with the formalism of Kármán–Howarth–Monin equation(s) are touched upon. [ABSTRACT FROM AUTHOR]

Up until the twentieth century, fluid mechanics was characterised by a strong division between theory and practice. The formulas of mathematicians and physicists were difficult to apply experimentally and their relevance was neither well accepted nor well understood by engineers. In France, where priority was given to the theoretical aspects of this subject, the creation of several centres of fluid mechanics in the 1930s (Lille, Marseille, Paris and Toulouse) represented an attempt at a rapprochement between fluid mechanics, experimental aerodynamics, and hydrodynamics. The aim was to re-establish France's international profile, which had been lost after 1918. In Lille, the leadership of the “Institut de mécanique des fluides” (IMFL) was entrusted to Jospeh Kampé de Fériet, who was able to address questions of both theoretical and experimental nature in the context of his work at the IMFL and at the “Commission de la turbulence atmosphérique”. On the one hand, Kampé de Fériet used a probabilistic approach to give greater mathematical rigour to the statistical theory of turbulence due to Taylor–von Kármán. On the other hand, he played an active part in his group's experimental research on atmospheric turbulence. This paper aims to show in what way Kampé de Fériet's approach to fluid mechanics enabled him to contribute to the international development of the statistical theory of turbulence during the interwar period. [ABSTRACT FROM AUTHOR]

This paper presents a method to estimate reflected and transmitted wave amplitude spectra in a bounded domain such as a wave tank, when available data signals must be shortened due to interferences and wall effects. This paper extends the well known Goda and Suzuki two-probe method to three probes. The paper also suggests solutions to compute reliable transmission and reflection coefficients in spite of problems linked to higher harmonics and to the interference between different wave trains propagating in the tank. To cite this article: G. Duclos, A.H. Cle´ment, C. R. Mecanique 331 (2003). [Copyright &y& Elsevier]

The temporal stability of Poiseuille flow in viscoelastic tube has been studied by the author in a set of papers. In this paper the spatio-temporal stability of the foregoing system is examined. The method of orthnormalization is used in the numerical computation leading to an efficient algorithm to solve for an infinitesimal axisymmetric and nonaxisymmetric disturbances. Then a new method for eigenmodes search technique is founded which eliminates the need for the recurrence formula, developed previously by the author, in order to find the eigenmodes of the system. This new technique leads to more efficient and tractable algorithm to inspect the dispersion relation of the system in the complex wave number and frequency planes. The nature of the instabilities depends on the boundary conditions imposed at the outside tube surface. In the range of physical parameters taken into account in this paper, it is found that for a noncollapsible tube one of the two axisymmetric unstable modes represents an absolute instability. For collapsible tube, the absolute instability is induced by a set of nonaxisymmetric modes. The ratio of the frequency of these absolute unstable modes in their cusp points are in good agreement with the experimental finding. The absolute instability is introduced by solid-based mode. To cite this article: M. Hamadiche, C. R. Mecanique 330 (2002) 769–775. [Copyright &y& Elsevier]

Résumé Cette note présente une méthode mécanique pour la détermination de la porosité totale d'un sol. La méthode présentée consiste à placer un échantillon de sol dans une cellule régulée dont on peut faire varier le volume par paliers grâce à un piston. La porosité du sol se déduit de la variation de la pression totale de la phase gazeuse lors des incréments de volume. La méthode a été validée sur un sol en considérant cinq échantillons de porosités différentes. Les résultats expérimentaux sur la porosité totale sont en bon accord avec les résultats théoriques sur l'ensemble des essais réalisés. This paper presents a mechanical method for the determination of the total porosity of soil. The presented method consists in inserting a sample of soil into a cell that can be regulated by varying the volume of the gas by increments using a piston. The porosity of the soil is deduced from the variation of the total pressure of the gaseous phase during the realization of volume increments. The method has been validated on a soil considering five samples with different porosities. The experimental results on the total porosity are in good agreement with the theoretical results over all tests. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates the instability of a viscoelastic fluid in a saturated porous medium heated from below and subjected to an horizontal through-flow. The Oldroyd-B constitutive equation is used to describe the viscoelastic behavior of diluted polymeric solutions. In the absence of the horizontal flow, the onset of convection can be characterized either by stationary or oscillatory instabilities. A temporal stability analysis is carried out in order to study the combined influence of the viscoelastic properties of the fluid and the main flow on the linear characteristics of these two types of instabilities. It is shown that the presence of the through-flow has a destabilizing effect and that it favors the emergence of mobile transverse rolls (R.T.), among an infinity of three-dimensional unstable modes. The thresholds for the appearance of these R.T., as well as their wavelengths and frequencies, are determined as functions of the dimensionless parameters of the problem. [Copyright &y& Elsevier]

Abstract: To determine the strain and stress in the biological soft tissues such as ligaments, tendons or arterial walls, anisotropic hyperelastic constitutive laws are often used in the context of finite element analysis [J.A. Weiss, B.N. Maker, S. Govindjee, Finite element implementation of incompressible, transversely isotropic hyperelasticity, Comp. Meth. Appl. Mech. Engng. 135 (1996) 107–128]. In the present paper, we propose to realize such a study together with a analytical study. This study allows for the understanding of the reason why it does not exist a one-to-one correspondence between the principal stretch and the fourth invariant of the dilatation tensor for the material model proposed by Holzapfel, Gasser and Ogden [G.A. Holzapfel, T.C. Gasser, R.W. Ogden, A new constitutive framework for arterial wall mechanics and a comparative study of material models, J. Elasticity 61 (2000) 1–48; T.C. Gasser, R.W. Ogden, G.A. Holzapfel, Hyperelastic modelling of arterial layers with distributed collagen fibre orientations, J. R. Soc. Interface 3 (2006) 15–35]. In fact, the relationship becomes non-bijective when the angle between the collagen fibers and the circumferential direction is greater that a critical angle of 54.73°. Importance of this critical angle was also discussed by Guo et al. (2006). To cite this article: F. Peyraut et al., C. R. Mecanique 337 (2009). [Copyright &y& Elsevier]

Abstract: A granular structure is an aggregation of grains whose sizes are characterized by a given distribution. A sample of this kind of structure is often modeled by a rectangle filled with disks in two dimensions or a parallelepiped containing spherical balls in three dimensions. Therefore, the geometrical modeling of such a structure consists in determining a “dense” repartition of disjoint disks (or spherical balls) with respect to the specified size distribution. In this paper, a new sphere packing algorithm based on an advancing-front approach, commonly used in meshing methods, is proposed. Significant improvements in computing time and density have been obtained comparing to existing methods. In addition, we show that the generated circular grains can be transformed into polygonal (polyhedral) cells generally observed in reality. An example of a metallic nanostructure model is presented. To cite this article: P. Laug et al., C. R. Mecanique 336 (2008). [Copyright &y& Elsevier]

Abstract: This paper concerns the influence of temperature on the water retention curve of porous media. We present a model based on the differential of suction as a function of temperature, water content and void ratio. When adjusted for a given temperature, this model is able to predict the curve for any temperature. The model was validated by several tests on a ceramic (terra cotta) and a clayey silty sand at 20 and 60 °C. The application of the model to data found in the literature confirms its predictive power for a wide range of porous materials. To cite this article: S. Salager et al., C. R. Mecanique 334 (2006). [Copyright &y& Elsevier]

Abstract: We attempt here to use the kinematic method of yield design in the case of a porous medium subjected to flow (with or without free surface), without looking for the exact solution of the pressure field. The method proposed here is based on the use of approximate pressure fields. In this paper, we show how, under different conditions concerning the yield criterion and the velocity field, the use of such approximate fields allows one to obtain a necessary condition for stability without having to find the real pressure field. To cite this article: A. Corfdir, C. R. Mecanique 334 (2006). [Copyright &y& Elsevier]

Abstract: The bi-potential method has been successfully applied for the modeling of frictional contact problems in static cases. This paper presents the application of this method for dynamic analysis of impact problems with multiple deformable bodies. A first order algorithm is applied for numerical integration of the time-discretized equation of motion. The numerical results show clearly the physical energy dissipation introduced by frictional effects between the solids in contact. To cite this article: B. Magnain et al., C. R. Mecanique 333 (2005). [Copyright &y& Elsevier]

The knowledge of response times of active material is essential for their efficient use as actuators. In this paper the heating and cooling times of a shape memory alloy wire (NiTi) under a constant load are predicted by the integration of the corresponding heat equation. The comparison with a ‘fictitious’ material with the same material characteristics but without phase transformation shows that the response times are longer for the SMA (around 2.7 times for heating and 1.5 times for cooling). To cite this article: N. Chaillet et al., C. R. Mecanique 332 (2004). [Copyright &y& Elsevier]

The high-cycle fatigue criteria based on a macroscopic–mesoscopic scale interpretation, initiated by Dang Van, were used essentially for polycrystalline materials. In the existing criteria the material isotropy at both mesoscopic and macroscopic scales plays a key role. The purpose of this paper is to revisit the macroscopic to mesoscopic fatigue approach taking into account the material anisotropy and some results obtained by Bui. The possible applications are some anisotropic steels or monocrystalline structures such as stitanium turbine blades. To cite this article: F. Cano et al., C. R. Mecanique 332 (2004). [Copyright &y& Elsevier]

In this paper, a differentially heated square/cubic cavity is studied by performing three-dimensional direct numerical simulations. The first bifurcation observed at Ra≈3.2×107 is due to the 3D vortex structures generated at the end regions of vertical boundary layers near the median plane. The main results of this Note are that the flow returns to a steady state for higher values of the Rayleigh number Ra (7×107 and 108 for example) still exhibiting these 3D vortex structures, and that multiple steady flows which differ by their symmetry properties, are obtained for Ra=108. However, the flow reverts to unsteadiness for Ra=3×108. In this latter case, the instability is due to the vertical boundary layers. To cite this article: G. de Gassowski et al., C. R. Mecanique 331 (2003). [Copyright &y& Elsevier]

This paper describes a dynamical strategy for releasing micro objects picked-up by means of adhesion forces. While sticking effects are used in order to capture an object by adequately choosing a high surface energy constitutive material for the end-effector, these same effects handicap considerably the release. We propose to take advantage of the inertial effects of both the end-effector and the manipulated object to overbalance adhesion forces and to achieve the release. Simulations show that for this purpose, accelerations as high as 105 m/s2 are needed. Successful manipulation of a 40 μm radius glass sphere is demonstrated. To cite this article: S. Haliyo et al., C. R. Mecanique 331 (2003). [Copyright &y& Elsevier]

This paper presents a study devoted to the composite fabric shaping simulation in finite strain analysis. We introduce a new geometrical approach based on the fishnet method for which the deformation of a fabric mesh element consists in a pure trellis effect. Such a fabric mesh element is then defined by a curved quadrilateral whose edges are geodesic lines with the same length plotted onto the surface to drape. Given three vertices of the fabric mesh element on the surface, we propose an optimization algorithm to define the fourth vertex of the fabric mesh element. This algorithm allows us to drape the surface using an advancing front approach from the data of an initial impact point between the fabric and the surface and the initial fibre directions at this point. A numerical draping simulation example using this approach is given. To cite this article: H. Borouchaki, A. Cherouat, C. R. Mecanique 331 (2003). [Copyright &y& Elsevier]

A porous medium, which matrix is a perfectly plastic solid, is considered. This paper proposes a method to determine the macroscopic admissible stress states. The method is based on a homogenization technique which takes advantage of the equivalence, under certain conditions, between a problem of limit analysis and a ficticious nonlinear elastic problem. The particular case of a Drucker–Prager solid matrix is considered. The method provides an analytical expression for the complete macroscopic strength criterion. To cite this article: J.-F. Barthe´le´my, L. Dormieux, C. R. Mecanique 331 (2003). [Copyright &y& Elsevier]

The sequential iterative approach (SIA) scheme is the most efficient method for modelling reactive transport in porous media with the operator-splitting approach. A combination of finite discontinuous and finite mixed-hybrid elements is a powerful method for solving solute transport in porous media, but the use of this method for SIA scheme induces numerical difficulties. In this paper, a new method is developed to solve reactive transport by using both the SIA scheme and a combination of finite discontinuous and finite mixed elements. The proposed method is tested by modelling a column experiment. To cite this article: J. Carrayrou et al., C. R. Mecanique 331 (2003). [Copyright &y& Elsevier]

This paper presents a study performed on a compacted swelling material in the range of suctions comprised between 8.5 and 287.9 MPa. Two series of tests were carried out with suction controlled oedometers. The aim of the first series was to study the compressibility as a function of suction. It showed that the apparent preconsolidation pressure and the plastic compression line are greatly affected by the applied suctions. The other series of tests highlighted the influence of complex hydromechanical paths on the compressibility of the studied material that appeared to be greatly influenced by the stress path followed. To cite this article: O. Cuisinier, F. Masrouri, C. R. Mecanique 331 (2003). [Copyright &y& Elsevier]

This paper describes numerical solutions of the Navier–Stokes equations for incompressible steady flow through a rigid smooth straight tube with an axially uniform non-circular cross section which mimics collapsed veins at peculiar values of the transmural pressure. One of the peculiar values of the transmural pressure produces a contact of the opposite walls along a straight segment. This article deals with the space variations of the wall shear stress induced along the wetted perimeter of the cross section as well as in the streamwise direction especially in the entry length. The motivation of this study is to provide the data for experimental works on flow-subjected endothelial cell culture when the space variations of the wall shear stress are non-uniform. To cite this article: S. Naili et al., C. R. Mecanique 330 (2002) 483–490. [Copyright &y& Elsevier]

The present paper demonstrates how the directional characteristics of an actual three-segment electrodiffusional sensor can be calculated from the probe image. It was shown that utilization of ‘ideal’ directional characteristics lead to an important (up to 15∘) error in flow angle determination. The directional characteristics calculated from the probe image improve significantly (up to 50%) the accuracy of the flow angle measurements. To cite this article: F. Barbeu et al., C. R. Mecanique 330 (2002) 433–436. [Copyright &y& Elsevier]

In this paper the convergence of the RVM for a complex flow is studied, in function of three discretization parameters. Two of these parameters are related to the spatial discretization of the vorticity Γ (sheet or blob strength) and h (sheet length or core radius) and the third one to the time discretization Δt. Two main events are observed: first, the computation works but the convergence is not attained, secondly the computation fails. The first behaviour is attributed to a lack of accuracy and the second to a lack of numerical stability. Once the stability conditions are satisfied, decreasing the value of parameters always leads to convergence. To cite this article: I. Mortazavi et al., C. R. Mecanique 330 (2002) 409–416. [Copyright &y& Elsevier]

This paper is concerned with the momentum transfer in a porous medium. The equations for the continuous equivalent medium are written by the averaging method but the closure is obtained using an extended thermodynamics. The resulting model corresponds to the Navier–Stokes equation, in which the force exerted by the solid matrix on the fluid satisfies of first order differential equation. This Navier–Stokes equation model with memory generalises the Darcy model with an integro-differential term. To cite this article: O. Se´ro-Guillaume, D. Calogine, C. R. Mecanique 330 (2002) 383–389. [Copyright &y& Elsevier]

This paper presents a new approach to interpolate the mechanical fields associated to a given mesh of the computational domain which satisfy the equilibrium equations together with the mechanical criteria which are quadratical in terms of these fields. The method is based on the diffuse approximation techniques. These allow us to construct a field of globally arbitrary order of continuity which approximates accurately the initial discrete mechanical fields. Indeed, the construction is based locally on the resolution of a quadratical optimisation problem under degenerate quadratical constraints for which we propose an analytical solution. The method is applied, in particular, to an equilibrium problem of elastoplastic solid with non linear hardening. To cite this article: P. Villon et al., C. R. Mecanique 330 (2002) 313–318. [Copyright &y& Elsevier]

This paper presents an investigation on laminar transient free convection along a vertical surface subjected to a periodical heat flux density. Numerical analysis show that heat transfer is improved when the over-heating period is inferior to the under-heating one and if the flow has reached its new steady state. To cite this article: T. de Lorenzo, C. R. Mecanique 330 (2002) 181–184. [Copyright &y& Elsevier]

This paper is devoted to a micromechanical study of elastic media containing fluid saturated mesocracks. Under the non-interacting mesocracks assumption, we present different thermodynamics potentials, which can be adopted for the description of the mechanical behaviour of this class of materials. To cite this article: V. Pense´e et al., C. R. Mecanique 330 (2002) 147–152. [Copyright &y& Elsevier]

This paper presents the study of mutual interactions between dispersed and continuous phase in Couette Taylor flow. The introduction of the dispersed phase is obtained by ventilation or by pressure drop in an airtight chamber. In the first instabilities, the dispersed phase generate a modification of the flow state, the cavitating flow being moreover characterised by an advance to the third instability. The dispersed phase first stands along each of the apparent azimuthal waves as a string of individual bubbles located near the core of the Taylor cells and then migrates to the outflow regions near the inner cylinder. To cite this article: H. Dje´ridi et al., C. R. Mecanique 330 (2002) 113–119. [Copyright &y& Elsevier]