Search

With connected vehicle technology, eco-driving strategies could bring benefits in decreasing traffic oscillation, reducing fuel consumption along with air pollution, and improving traffic mobility. This thesis proposes an eco-driving strategy to reduce traffic oscillation and smooth trajectories for vehicles at different traffic situations, including highway sections and urban traffic intersections. The eco-driving strategy assumes a connected vehicle environment, in which each vehicle exchanges information in real-time through vehicle-to-infrastructure (V2I) communications and vehicle-to-vehicle (V2V) communications. The proposed strategy devises the advisory speed and the control duration for each vehicle through various control algorithms that are available in different traffic situations. After receiving the information from V2I and V2V communications, each connected vehicle would apply a simple cruise control method during the control duration. The proposed algorithm determines proper advisory speed and control duration through a heuristic solution of the optimization model, which is a tangent line approach. The optimization model, which has the objective function to minimize the speed oscillation of each vehicle is applied at the origin or estimated trajectories under different traffic situations, including when vehicles are approaching a signalized intersection, non-signalized intersection, and following a moving bottleneck at an arterial road. Based on the optimization model, this study proposes a heuristic solution which is a tangent line method between control starting point to the estimated objective trajectories, with the slope of the tangent line serving as the static advisory speed applied for the vehicle. The kinematic wave analysis is applied for deriving or estimating vehicle objective trajectories at each traffic situation. In a highway with a slow-moving vehicle, this study solves a more generalized moving bottleneck problem to derive the traffic flow-rate and density upstream of the moving bottleneck, and get the following trajectory for each vehicle after the moving bottleneck. At traffic intersections, the kinematic wave analysis is first applied to describe vehicle start-up behaviors, and demonstrates the requirements for fully improving traffic efficiency. According to the requirements, the estimated time points (i.e., the passing points) are created for vehicles to pass through the intersection. Accordingly, the origin trajectories are estimated in order to make vehicles enter the intersection at each passing point with the designed optimal speed. For a signalized intersection, the passing points are created based on a specific signal plan of a given phasing. In addition, the eco-driving strategy could also be extended into a Cooperative Vehicle Intersection Control (CVIC) algorithm and applied at a non-signalized intersection. In this situation, the passing points are created and updated according to the previous vehicles passing through the intersection from different directions.The benefits of this strategy are presented from a set of numerical simulations, along with the sensitivity analysis with the flow-rate taken at the intersection situations. The simulations are conducted for each traffic situation. In the highway sections, four scenarios with different bottleneck movements are applied, where the moving bottleneck has a constant speed, accelerates, decelerates, and stops-and-goes. The results show that both speed variance and fuel consumption are reduced with the algorithm in each of the scenarios. At the signalized intersections, all vehicles applying the algorithm would never stop before the intersection and would pass through the intersection with the free-flow speed. The number of vehicles that could pass through the intersection also increases. Also, traffic oscillation is reduced when approaching the intersection. With the CVIC algorithm applying at the intersection, all vehicles could pass through the intersection with free-flow speed, and no traffic conflictions happens between vehicles. Furthermore, in an illustrative study, the algorithm reduces the total intersection delay by 34.95 % on average, the fuel consumption by 65.79 % on average, and the speed variance by 5.75 % on average. The simulation result shows the algorithm could be beneficial in decreasing traffic oscillation, reducing environmental impact, and improving traffic efficiency as well when applied at the intersections. The basic idea behind this study is to make a predictable time and speed for the vehicle to eliminate the moving bottleneck effects and to pass through the intersection. This information provides a theoretical basis for further optimizing the traffic flows through the V2I, V2V communications, and CAV technologies, which could be applied to various situations.

With the emergence of connected vehicle technologies, many interesting applications become possible. We look at one such application that allows trac system users with heterogeneous values of time (VOT) to trade their right of way (ROW) among other users so as to minimize individuals' total travel costs, which includes time cost and nancial transaction. Our proposed system allows users on a multi-lane road to trade their ROWs, and the resulting traffic flow violates the First-In-First-Out (FIFO) principle, since vehicles with higher VOTs would travel faster by paying those with lower VOTs. A novel multi-commodity kinematic wave model is developed for such a system based on the assumptions of choice, uniability, prices, budget-balance, utility maximization, referred to as A1 through A5.From these assumptions, we study a simple case of such a system in which two groups of users with different VOTs participate in the scheme, and a third group does not participate. We derive a uniable fundamental diagram in which the relative speed ratios of differentcommodities are constant and proportional to the square root of the VOTs. We show that the scheme is Pareto-improving at the system optimal solution. The Riemann Problem is solved both analytically and numerically for this system, and we demonstrate that differentcommodities (user groups) would react differently to shockwaves and rarefaction waves. The study is concluded with future extensions.

The Typhoon Hagibis in 2019 with heavy rainfall caused large-scale inundated damage in the College of Engineering, Nihon University and its surrounding areas. We need to understand the inundation mechanism caused by Typhoon Hagibis 2019 since it is concerned about the possibility of heavy rain frequently in Japan in the future. This study proposes a simplified estimation method for inundation height based on the kinematic wave model. The estimation result was validated by the measurement results to conduct field surveys. As a result,the difference between the measured and estimated inundation height was –0.15±0.28 m which was reasonable considering the accuracy of the digital elevation model from the Geospatial Information Authority of Japan.

This research concerns about the development and application of Variable Parameter Kinematic Wave Numerical model (VPKWM) based on 1-D Saint-Venant equation, to study the behaviour of the propagation of a flood wave in Non-prismatic natural waterways in an ungauged basin. The channel slope and wetted perimeter are considered as variable because of the irregularity of the boundary of the channel and the change in magnitude of discharge. The scarcity of reliable inflow data at upstream is a serious problem for the flood routing process in an ungauged basin. In this study the inflow hydrograph and lateral inflow hydrographs are obtained using SCS-CN method as rainfall runoff model. The performance of the model assessed considering four parameters such as root mean square error (RMSE), peak discharge, peak time and total volume. The results indicated that the VPKWM for non-prismatic channel provided reasonable output compared with the observed data.

Real-time control of urban drainage networks requires knowledge about stored volumes and flows in order to predict overflows and optimize system operation. However, using flow sensors inside the pipelines means prohibitively high installation and maintenance costs. In this article, we formulate two nonlinear, constrained estimation problems for identifying the open-channel flow in urban drainage networks. To this end, we distribute cost-efficient level sensors along the pipelines and formulate the estimation problems based on the spatially-discretized kinematic and diffusion wave approximations of the full Saint-Venant partial differential equations. To evaluate the capabilities of the two models, the two approaches are compared and evaluated on modeling a typical phenomenon occurring in drainage systems: the backwater effect. An extensive real-world experiment demonstrates the effectiveness of the two approaches in obtaining the model parameters on a scaled water laboratory setup, in the presence of measurement noise.

The Rational Formula (RF) is probably the most frequently applied equation in practical hydrology to compute the peak discharge, due to its simplicity and effective compromise between theory and data availability. Thus, after more than a century, the estimation of peak discharge through the RF is still an important and challenging issue in hydrology. The RF assumes response linearity and sometimes assumes that the return period does not depend on the runoff coefficient and neglects the time to ponding and the antecedent moisture condition. Moreover, the RF requires the critical duration of rainfall and the runoff coefficient to be estimated, both of which are highly controversial. This paper proposes an advanced RF that makes it possible to derive the peak discharge at the hillslope scale, where the above RF assumptions are mostly relaxed. Physically based runoff coefficient tables, which are not affected by subjectivity, are presented and application of the derived procedure is performed.

The Kinematic Wave Model (KWM), representing a simplification of the Full Wave Model (FWM) under the shallow-water approximation, is often used in the one-dimensional formulation for describing the dynamics of debris/mud flood. The present work investigates the applicability conditions of the KWM to analyze mud floods, characterized by a rheological behaviour expressed through a power-law model. The study is carried out through the numerical solution of both the Full and Kinematic Wave models changing the characteristic time of hydrograph, i.e. the wave duration, imposed at the channel inlet. The predictions of the two models are compared in terms of maximum flow depth, maximum discharge and peak discharge at the downstream channel end. The study is performed for several values of the Froude (F) and the Kinematic Wave (K) numbers. Similarly to the clear-water case, present results show that higher errors in applying KWM pertain to shorter flood wave durations, but the performance of KWM appears to strongly depend on the value of the rheological index, becoming worse as the fluid rheology becomes more shear-thinning. The study furnishes applicability criteria representing a guideline for practical applications in terms of minimum wave duration above which the KWM error in reproducing the considered flood characteristics (the maximum flow depth, the maximum discharge and the peak discharge at the downstream channel end) is less or equal than 5%. Finally, it has been shown that the wave period criterion, obtained considering linearized wave dynamics, may be safely applied at least for fluid with moderate shear-thinning behavior and for moderate values of the dimensionless number KF2.

Although soil erosion is one of the main threats to agriculture sustainability in many areas of the world, its processes are difficult to measure and still need a better characterization. The use of iron oxides as sediment tracers, combined with erosion and mixing models opens up a pathway for improving the knowledge of the erosion and redistribution of soil, determining sediment sources and sinks. In this study, magnetite and a multivariate mixing model were used in rainfall simulations at the micro-plot scale to determine the source of the sediment at different stages of a furrow–ridge system both with (+T) and without (–T) wheel tracks. At a plot scale, magnetite, hematite and goethite combined with two soil erosion models based on the kinematic wave approach were used in a sprinkler irrigation test to study trends in sediment transport and tracer dynamics along furrow lengths under a wide range of scenarios. In the absence of any stubble cover, sediment contribution from the ridges was larger than the furrow bed one, almost 90%, while an opposite trend was observed with stubble, with a smaller contribution from the ridge (32%) than that of the bed, at the micro-plot trials. Furthermore, at a plot scale, the tracer concentration analysis showed an exponentially decreasing trend with the downstream distance both for sediment detachment along furrows and soil source contribution from tagged segments. The parameters of the distributed model KINEROS2 have been estimated using the PEST Model to obtain a more accurate evaluation. Afterwards, this model was used to simulate a broad range of common scenarios of topography and rainfall from commercial farms in southern Spain. Higher slopes had a significant influence on sediment yields while long furrow distances allowed a more efficient water use. For the control of runoff, and therefore soil loss, an equilibrium between irrigation design (intensity, duration, water pattern) and hydric needs of the crops should be defined in order to establish a sustainable management strategy., This work was funded by the Spanish Ministry of Science and Innovation (Projects AGL2006-10927-C03-01, AGL2006-10927-C03-02 and AGL2009-12936-C03-01), the Project P09-AGR-4782 of the Consejería of Economy, Innovation and Science of the Junta de Andalucía, and FEDER funds.

Derived from simplifications of the Saint-Venant equations, the kinematic wave model has the ability to describe the behavior of surface runoff in watersheds. This paper aims to obtain the numerical simulation of the flow routing in a natural watershed, by using lattice Boltzmann method. In the computational model, the surface of the basin will be represented by a V-shaped segmented in two lateral planes and one main channel. The simulation considers the effective precipitation flowing on the watershed per unit of width at the exit of each of the planes that represent the surface of the basin. The water flowing from the planes enters the main channel in the form of lateral contribution. Hydrograms of two rain events are obtained, which present the volume drained in the outlet corresponding to the whole basin in each event. Two equilibrium distribution functions were developed by Chapmann-Enskog expansion at time scales and model D1Q3, one suitable for flow on the basin surface and another for the main channel, in order to obtain the variables of interest in each case. The numerical results obtained were compared with the KINEROS2 hydrological model.

Doğada bulunan akarsuların enkesitleri genel olarak düzensiz biçimdedir. Fakat bu akarsularda zorunlu olarak taşkın öteleme hesaplamaları yapılmaktadır. Taşkın öteleme hesaplamaları için Saint-Venant denklemlerinden yararlanılarak akarsuda matematiksel modelleme yapılır. Matematiksel modelleme için akarsuyun enkesiti en basit prizmatik şekil ile temsil edilebilmektedir. Matematiksel modelleme sonucunda kinematik dalga modeli, difüzyon dalga modeli ve dinamik dalga modeli olmak üzere üç dalga modeli geliştirilmiştir. Bu dalga modellerinin sayısal çözümünde genel olarak sonlu fark yaklaşımları kullanılmıştır. Bu çalışmada üç farklı prizmatik kanal için dalga modellerinin kıyaslanması, dalga modellerindeki ihmallerin taşkın hidrografına etkisi ve kanal parametrelerinin (taban eğimi, taban genişliği, şev eğimi ve Manning pürüzlülük katsayısı) taşkın hidrografının karakteristik yapısına olan etkileri incelenmiştir. Cross-sections of rivers in the nature are generally irregular. However, flood routing calculations are necessarily performed in these rivers. Mathematical modeling is done in rivers using the Saint-Venant equations for flood routing calculations. For mathematical modeling, the cross-section of the river can be represented by the simplest prismatic shape. Matematiksel modelleme sonucunda üç dalga modeli geliştirilmiştir. These are kinematic wave model, diffusion wave model and dynamic wave model. In the numerical solution of these wave models, finite difference approximations in general used. In this study, the effects of wave models for three different prismatic channels, the effects of flood hydrographs on omissions in wave models, and the effects of channel parameters (channel bottom slope, base width, energy line slope, incline of slope and Manning roughness coefficient) on the characteristic structure of the flood hydrograph have been examined.

Dissertação de Mestrado Integrado em Engenharia do Ambiente apresentada à Faculdade de Ciências e Tecnologia A forma é uma das caraterísticas fisiográficas que influência na resposta hidrológica das bacias hidrográficas. Este trabalho avalia esta influência em termos de escoamento superficial e transporte de sedimentos. Foram conduzidas experiências em laboratório com recurso a um simulador de chuva e três parcelas de terra. Em cada parcela foram simulados 4 eventos de precipitação com a mesma duração, intercalados com 16 minutos sem precipitação. Os resultados experimentais sugerem que o caudal de ponta diminui com o aumento do comprimento no sentido do escoamento, exceto para os primeiros eventos de precipitação. A quantidade de sedimentos transportados diminuiu com o aumento do comprimento, para todos os eventos de precipitação. No entanto a quantidade de sedimentos transportados foi menor no último evento de precipitação para todas as parcelas. Os resultados experimentais de escoamento superficial foram comparados com as do modelo da onda cinemática, resolvida com um método de diferenças finitas. Houve um bom ajuste entre os resultados experimentais e os numéricos, com melhores ajustes para as parcelas com maior comprimento. Uma análise de sensibilidade mostrou que os ajustes seriam melhores com um aumento do coeficiente de Manning ou com a diminuição da inclinação, exceto no último evento de precipitação. No modelo da onda cinemática foram simulados várias formas das parcelas, sendo a forma expressa por um fator de forma que relaciona o quadrado do comprimento com a área das parcelas. A forma das parcelas influenciou o escoamento superficial. No entanto não houve grandes diferenças na previsão do caudal de ponta. As maiores diferenças entre as formas foram verificadas na fase ascendente e descendente dos hidrogramas. Com o aumento do fator de forma, o escoamento iniciou-se mais tarde atingindo um caudal de ponta menor e com decréscimo mais lento no escoamento depois do fim da precipitação. The shape is one of the physiographic features that influence the hydrological response of the drainage basin. This work evaluates this influence in terms of surface runoff and sediment transport. Experiments were conducted in the laboratory using a rainfall simulator and three plots. In each plot, 4 rainfall events with the same duration were simulated, interspersed with 16 minutes without precipitation. Experimental results suggest that peak flow decreases with increasing runoff length, except for the first precipitation events. The amount of transported sediment decreased with increasing length for all precipitation events. However, the amount of sediment transported was lower in the last precipitation event for all plots. The experimental results of surface runoff were compared with those of the kinematic wave model, solved with a finite difference method. There was a good fit between the experimental and numerical results, with better adjustments for the more elongated plots. A sensitivity analysis showed that the adjustments would be better with an increase in the Manning coefficient or with the slope decrease, except in the last precipitation event. In the kinematic wave model different shapes of the plots are simulated, with the shape being expressed by a shape factor that relates the square of the length with the area of the plots. The shape of the plots influenced the runoff. However, there were no major differences in the peak flow forecast. The greatest differences between the shapes were verified in the rising and falling limb of the hydrographs. With the increase of the shape factor, the surface runoff started later reaching a lower peak flow and slower decrease in surface runoff after the end of the precipitation.

On freeways, congestion always leads to capacity drop. This means the queue discharge rate is lower than the pre-queue capacity. Our recent research findings indicate that the queue discharge rate increases with the speed in congestion, that is the capacity drop is strongly correlated with the congestion state. Incorporating this varying capacity drop into a kinematic wave model is essential for assessing consequences of control strategies. However, to the best of authors’ knowledge, no such a model exists. This paper fills the research gap by presenting a Lagrangian kinematic wave model. “Lagrangian” denotes that the new model is solved in Lagrangian coordinates. The new model can give capacity drops accompanying both of stop-and-go waves (on homogeneous freeway section) and standing queues (at nodes) in a network. The new model can be applied in a network operation. In this Lagrangian kinematic wave model, the queue discharge rate (or the capacity drop) is a function of vehicular speed in traffic jams. Four case studies on links as well as at lane-drop and on-ramp nodes show that the Lagrangian kinematic wave model can give capacity drops well, consistent with empirical observations.

International audience; This paper revisits the variational theory of traffic flow, now under the presence of continuum lateral inflows and outflows to the freeway say Eulerian source terms. It is found that a VT solution can be easily exhibited only in Eulerian coordinates when source terms are exogenous meaning that they only depend on time and space, but not when they are a function of traffic conditions, as per a merge model. In discrete time, however, these dependencies become exogenous, which allowed us to propose improved numerical solution methods. In Lagrangian and vehicle number-space coordinates, VT solutions may not exist even if source terms are exogenous.

Water excess during winter limits crop development on heavy clay soil conditions of the Gharb valley (Morocco). The furrow system to eliminate these negative effects is the adopted solution. This article focuses on the development of a water transfer model through a furrow system during unsteady rainfall event to evaluate the runoff volume resulting from a reference rainy event. This model contains a production function associated to a transfer function. The production function is based on the Green–Ampt infiltration equation. The latter has been adapted to account for unsteady rain conditions and rainfall intermittence. The transfer function is based on the kinematic wave model, the explicit solution of which is coupled with the water excess generated by the production function. Simulated runoff in the furrows is collected by a drainage ditch evacuating the flow outside a plot of 1.3 ha. The similarity between parameters of a furrow irrigation model and those of the production function is advantageously used for model calibration. The proposed modelling approach shows capabilities to predict water amount and peak discharges evacuated from a plot of around 1 ha by a furrow system under unsteady rainfall events. As an application, it is used to evaluate the ability of the surface drainage system to evacuate the excessive volumes of water under typical rainfalls.

乾燥地域では，乾季には水不足になる一方で雨季になると急に出水して洪水が起こるなど，様々な水資源問題が発生している。本研究は，乾燥域における持続可能な治水・利水方法を提案することを目的とし，ワジの流出特性を把握するべく提案モデルを用いて解析を行った。その結果，断続的な表流水現象の再現，移動損失量分布の推定などワジにおける流出特性を再現推定することが出来た。また，様々なワジを比較することにより，流出特性や気候特性がワジに与える影響を示すことができた。, The arid and semi-arid regions are characterized by scarcity of water resources, an ever-increasing demand on water supplies, the paucity of data, drought and flash flood threat. So, this paper aims to introduce an effective methodology for sustainable management and efficient utilization of the water resources as well as flood control in the arid regions to sustain a minimum resource base. A physically-based, distributed hydrological model was proposed in W. Al-Khoud (Oman), W. Ghat (Saudi Arabia) and W. Assiut (Egypt). This approach can satisfactorily evaluate Wadi runoff behaviors such as discontinuously surface flow and estimating transmission losses. A comparison study has been done between different wadis to understand the effect of watershed characteristics and climatic condition on Wadi runoff. The results of numerical simulation exhibit good fitting with the observed ones however the paucity of high quality data.

高精度の観測値があまりない乾燥地のワジ機構の特徴として，表面流出で見る限りでは時空間的な不連続現象となる。本稿は，時空間的な断流河川の不連続現象を考慮しながら治水や水資源管理のためにワジ機構の分布型水文モデルを導出する。まず分布型水文モデルのパラメータをマクロスケールからメガスケールまでアップスケールする均質化手法を示す。この結果を用いてワジ機構の流出分布をシミュレーションを実行し，河道での移動損失が表面流や中間流・地下水流からその効果の評価を示した。この手法を使って表流水・地下水の有機的利用は大いに活用されるべきである。本モデルは乾燥地の分布型流出に関連する諸問題に応用可能であると言える。, It has been stated that the limitation of the development of arid zone hydrology is the lack of high quality observations. This paper introduces a distributed hydrological model of the Wadi system for flood control and water resources management considering the discontinuous occurrence of flow in both space and time. We provide a homogenization method of upscaling hydrologic parameters related to a distributed runoff model from macroscopic aspects up to megascopic ones. Discharge distribution of the Wadi system can be simulated. Transmission losses and their effects on surface and subsurface flow are evaluated. The conjunctive use of surface and subsurface water is recommended. It is concluded that this model is an applicable methodology for distributed discharge in the arid regions.

Nesta pesquisa se objetivou validar a simulação da irrigação por sulco, realizada pelo modelo SASIS através do procedimento matemático de ondas cinemáticas. Utilizam-se, na validação do modelo SASIS, 7 conjuntos de dados que representam diferentes condições de campo, em que o comprimento de sulco variou de 67 a 403 m, a declividade de 0,0016 a 0,0173 m m-1, a vazão de 1,1 a 2,0 L s-1 e o tipo de textura do solo de franco-arenoso a franco silte-argiloso. Para maior consistência da validação, as simulações realizadas por este modelo foram comparadas com as do modelo SIRMOD, além das comparações com as medições de campo. Para a maioria dos dados de campo estudados, as simulações da fase de avanço pelo modelo SASIS mostraram discrepâncias no tempo de avanço, no final da área, inferiores àquelas dadas pelo modelo SIRMOD, em relação às medições de campo. Novamente, para grande parte das condições de campo analisadas as discrepâncias entre os valores simulados pelo modelo SASIS e os medidos em campo do tempo de avanço no final da área, foram pequenas, a ponto de não comprometerem o prognóstico de parâmetros de dimensionamento, avaliação e manejo dos sistemas de irrigação por sulco.The aim of this research was to validate the simulation of furrow irrigation performed by the SASIS model through the mathematical procedure of kinematic waves. In the validation of the SASIS model, 7 data sets representing different field conditions were used, in which the furrow length varied from 67 to 403 m, the field slope from 0.0016 to 0.0173 m m-1, the inflow from 1.1 to 2.0 L s-1 and the soil texture type from sandy loam to silty clay loam. In order to give more consistency to the validation, the simulations accomplished by this model were compared with those from the SIRMOD model, and also compared with data from the field measurements. For most field data studied, the simulations of the advance phase by SASIS model presented discrepancies in the advance time at the end of the area, being inferior to the ones given by SIRMOD model, in relation to field measurements. Again, for the greater part of field conditions analyzed, the discrepancies between the values simulated by SASIS model and those measured in field of the advance time at the end of the area were small, to the point of not compromising the prognostic of design, evaluation and management parameters of furrow irrigation systems.

For the appropriate management of water resources in a watershed, it is essential to calculate the time distribution of runoff for the given rainfall event. In this paper, a kinematic-wave-based distributed watershed model using finite element method (FEM), geographical information systems (GIS) and remote-sensing-based approach is presented for the runoff simulation of small watersheds. The kinematic wave equations are solved using FEM for overland and channel flow to generate runoff at the outlet of the watershed concerned. The interception loss is calculated by an empirical model based on leaf area index (LAI). The Green-Ampt Mein Larson (GAML) model is used for the estimation of infiltration. Remotely sensed data has been used to extract land use (LU)/land cover (LC). GIS have been used to prepare finite element grid and input files such as Manning's roughness and slope. The developed overland flow model has been checked with an analytical solution for a hypothetical watershed. The model has been applied to a gauged watershed and an ungauged watershed. From the results, it is seen that the model is able to simulate the hydrographs reasonably well. A sensitivity analysis of the model is carried out with the calibrated infiltration parameters, overland flow Manning's roughness, channel flow Manning's roughness, time step and grid size. The present model is useful in predicting the hydrograph in small, ungauged watersheds. Copyright © 2007 John Wiley & Sons, Ltd.

In this contribution a model-based analysis of the application of bounded acceleration in traffic flow is considered as a cause for the capacity drop. This is performed in a Lagrangian formulation of the kinematic wave model with general vehicle specific characteristics. Unconstrained overtaking is presumed, which allows a demonstration to be given of the influence that constraints in traffic flow may have on the capacity drop. An experimental case demonstrates that bounded acceleration in traffic flow with unconstrained overtaking has very limited effect on the capacity drop. This implies that the capacity drop when incurred through bounded acceleration must make use of (semi-)constrained traffic flow, in which variety in vehicle acceleration ability may also be required to increase inhomogeneity. This is an important conclusion as it further defines the conditions required for capacity drop. The application of a Lagrangian formulation with advection invariant combined with bounded acceleration is also novel. The contribution further shows that the application of bounded acceleration in the presented model is feasible, although adjustments are required to capture the capacity drop through bounded acceleration.

We present a continuous-time link-based kinematic wave model (LKWM) for dynamic traffic networks based on the scalar conservation law model. Derivation of the LKWM involves the variational principle for the Hamilton-Jacobi equation and junction models defined via the notions of demand and supply. We show that the proposed LKWM can be formulated as a system of differential algebraic equations (DAEs), which captures shock formation and propagation, as well as queue spillback. The DAE system, as we show in this paper, is the continuous-time counterpart of the link transmission model. In addition, we present a solution existence theory for the continuous-time network model and investigate continuous dependence of the solution on the initial data, a property known as well-posedness. We test the DAE system extensively on several small and large networks and demonstrate its numerical efficiency., 39 pages, 14 figures, 2 tables, Transportmetrica B: Transport Dynamics 2015

In this contribution a model-based analysis of the application of bounded acceleration in traffic flow is considered as a cause for the capacity drop. This is performed in a Lagrangian formulation of the kinematic wave model with general vehicle specific characteristics. Unconstrained overtaking is presumed, which allows a demonstration to be given of the influence that constraints in traffic flow may have on the capacity drop. An experimental case demonstrates that bounded acceleration in traffic flow with unconstrained overtaking has very limited effect on the capacity drop. This implies that the capacity drop when incurred through bounded acceleration must make use of (semi-)constrained traffic flow, in which variety in vehicle acceleration ability may also be required to increase inhomogeneity. This is an important conclusion as it further defines the conditions required for capacity drop. The application of a Lagrangian formulation with advection invariant combined with bounded acceleration is also novel. The contribution further shows that the application of bounded acceleration in the presented model is feasible, although adjustments are required to capture the capacity drop through bounded acceleration. © 2015 IEEE.

山腹表層付近の流れのモデルの基礎として、多孔質媒体内の不飽和/飽和流れのモデルが考えられる。しかし、実際の流域斜面の流れは、場の形態と媒体の性質の構造的不均一性の強い影響を受けるので、一般的な多孔質媒体内の流れのモデルよりも、流域場の構造的不均一性を考慮したモデルの方が、流出の特徴をよりょく表現できる可能性がある。本研究では、圃場容水量を導入したkinematicwaveモデルで飽和/不飽和流れを表現し、パイプ1みずみち流れを指数法則kiematicwaveモデルで表現し、これらを結合した形の計算モデルを構築する。, As a model of flow near mountain slopes, a saturated‐unsaturated flow model in porus media can be considered. However, since actual runoff process in mountain slopes is affected strongly by the shape of the flow field and structural nonhomogeneity of the media, those models which consider those effect explicitly may express the characteristics of runoff better than a general model of flow in porus media.In this study, saturated‐unsaturated flow is expressed by combining field capacity model and the surface‐subsurface kinematic wave model, pipe flow is modeled by the power‐law kinematic wave model, and a model which combines those model is presented. Numerical calculation methods of those models are also presented.

This work develops a grid based rainfall-runoff model (GRM), which is a physically based and spatially distributed model. Surface flow was analyzed using a kinematic wave model with the governing equations discretized using the finite volume method (FVM). This paper suggests a grid network flow analysis technique using variable rainfall intensity according to the flow directions to analyze one-dimensional flows between the grids. The model was evaluated by applying it to the Wuicheon watershed, a tributary of the Nakdonggang (Riv.), in Korea. The results showed that the grid-based, one-dimensional kinematic wave model adopted the FVM and the grid network flow analysis technique well. The simulation results showed good agreement with the observed hydrographs and the initial soil saturation ratio was most sensitive to the modeling results.

Nesta pesquisa se objetivou validar a simulação da irrigação por sulco, realizada pelo modelo SASIS através do procedimento matemático de ondas cinemáticas. Utilizam-se, na validação do modelo SASIS, 7 conjuntos de dados que representam diferentes condições de campo, em que o comprimento de sulco variou de 67 a 403 m, a declividade de 0,0016 a 0,0173 m m-1, a vazão de 1,1 a 2,0 L s-1 e o tipo de textura do solo de franco-arenoso a franco silte-argiloso. Para maior consistência da validação, as simulações realizadas por este modelo foram comparadas com as do modelo SIRMOD, além das comparações com as medições de campo. Para a maioria dos dados de campo estudados, as simulações da fase de avanço pelo modelo SASIS mostraram discrepâncias no tempo de avanço, no final da área, inferiores àquelas dadas pelo modelo SIRMOD, em relação às medições de campo. Novamente, para grande parte das condições de campo analisadas as discrepâncias entre os valores simulados pelo modelo SASIS e os medidos em campo do tempo de avanço no final da área, foram pequenas, a ponto de não comprometerem o prognóstico de parâmetros de dimensionamento, avaliação e manejo dos sistemas de irrigação por sulco. The aim of this research was to validate the simulation of furrow irrigation performed by the SASIS model through the mathematical procedure of kinematic waves. In the validation of the SASIS model, 7 data sets representing different field conditions were used, in which the furrow length varied from 67 to 403 m, the field slope from 0.0016 to 0.0173 m m-1, the inflow from 1.1 to 2.0 L s-1 and the soil texture type from sandy loam to silty clay loam. In order to give more consistency to the validation, the simulations accomplished by this model were compared with those from the SIRMOD model, and also compared with data from the field measurements. For most field data studied, the simulations of the advance phase by SASIS model presented discrepancies in the advance time at the end of the area, being inferior to the ones given by SIRMOD model, in relation to field measurements. Again, for the greater part of field conditions analyzed, the discrepancies between the values simulated by SASIS model and those measured in field of the advance time at the end of the area were small, to the point of not compromising the prognostic of design, evaluation and management parameters of furrow irrigation systems.

Transient bed profiles in alluvial channels are generally modeled using diffusion (or dynamic) waves and assuming equilibrium between detachment and deposition rates. Equilibrium sediment transport can be considerably affected by an excess (or deficiency) of sediment supply due to mostly flows during flash floods or floods resulting from dam break or dike failure. In such situations the sediment transport process occurs under nonequilibrium conditions, and extensive changes in alluvial river morphology can take place over a relatively short period of time. Therefore the study and prediction of these changes are important for sustainable development and use of river water. This study hence developed a mathematical model based on the kinematic wave theory to model transient bed profiles in alluvial channels under nonequilibrium conditions. The kinematic wave theory employs a functional relation between sediment transport rate and concentration, the shear-stress approach for flow transport capacity, and a relation between flow velocity and depth. The model satisfactorily simulated transient bed forms observed in laboratory experiments.

As a model of flow near mountain slopes, a saturated‐unsaturated flow model in porus media can be considered. However, since actual runoff process in mountain slopes is affected strongly by the shape of the flow field and structural nonhomogeneity of the media, those models which consider those effect explicitly may express the characteristics of runoff better than a general model of flow in porus media.In this study, saturated‐unsaturated flow is expressed by combining field capacity model and the surface‐subsurface kinematic wave model, pipe flow is modeled by the power‐law kinematic wave model, and a model which combines those model is presented. Numerical calculation methods of those models are also presented.