The Experts below are selected from a list of 6 Experts worldwide ranked by ideXlab platform
K Davari - One of the best experts on this subject based on the ideXlab platform.
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hysteresis phenomenon and modeling in soil water Relationship
Iran Agricultural Research, 2010Co-Authors: Azizallah Izady, Bijan Ghahraman, K DavariAbstract:Hysteresis has been widely recognized in the soil water Relationship. In this paper, a detailed review of hysteresis was performed in relation to its models. So far, different models have been suggested to describe hysteresis in the water retention curve (WRC) that could be categorized into two main groups: conceptual and empirical models. The models in the first group are based on the domain theory of capillary hysteresis and those in the second group rely on the analysis of observed WRC shape and properties. Conceptual models include the independent and dependent domain theories and the Parlange's model, while empirical models consist of the interpolation, linear, Slope and Scaling – down models. Different results of studies carried out by several researchers showed that the Parlange model, that uses the concept of rational extrapolation, was the best model to predict hysteresis of the WRC.
Azizallah Izady - One of the best experts on this subject based on the ideXlab platform.
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hysteresis phenomenon and modeling in soil water Relationship
Iran Agricultural Research, 2010Co-Authors: Azizallah Izady, Bijan Ghahraman, K DavariAbstract:Hysteresis has been widely recognized in the soil water Relationship. In this paper, a detailed review of hysteresis was performed in relation to its models. So far, different models have been suggested to describe hysteresis in the water retention curve (WRC) that could be categorized into two main groups: conceptual and empirical models. The models in the first group are based on the domain theory of capillary hysteresis and those in the second group rely on the analysis of observed WRC shape and properties. Conceptual models include the independent and dependent domain theories and the Parlange's model, while empirical models consist of the interpolation, linear, Slope and Scaling – down models. Different results of studies carried out by several researchers showed that the Parlange model, that uses the concept of rational extrapolation, was the best model to predict hysteresis of the WRC.
Bijan Ghahraman - One of the best experts on this subject based on the ideXlab platform.
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hysteresis phenomenon and modeling in soil water Relationship
Iran Agricultural Research, 2010Co-Authors: Azizallah Izady, Bijan Ghahraman, K DavariAbstract:Hysteresis has been widely recognized in the soil water Relationship. In this paper, a detailed review of hysteresis was performed in relation to its models. So far, different models have been suggested to describe hysteresis in the water retention curve (WRC) that could be categorized into two main groups: conceptual and empirical models. The models in the first group are based on the domain theory of capillary hysteresis and those in the second group rely on the analysis of observed WRC shape and properties. Conceptual models include the independent and dependent domain theories and the Parlange's model, while empirical models consist of the interpolation, linear, Slope and Scaling – down models. Different results of studies carried out by several researchers showed that the Parlange model, that uses the concept of rational extrapolation, was the best model to predict hysteresis of the WRC.
Mingtsan Wang - One of the best experts on this subject based on the ideXlab platform.
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a numerical model of infiltration processes for hysteretic flow coupled with mass conservation
Irrigation and Drainage, 2009Co-Authors: Chuhui Chen, Kaiyuan Ke, Mingtsan WangAbstract:The study presents a numerical infiltration model of a hysteretic flow coupled with general mass conservation for practical application to unsaturated soil. In unsaturated soil, hysteresis is an important phenomenon in the complicated hydrological processes, and it is usually ignored when simulating the Relationship of soil water content. The governing equation of unsaturated flow is the Richards equation, and it is difficult to obtain the analytic solutions because of the variation of temporal boundary conditions and the dynamics of change of soil water content in the vadose zone. The numerical solution is solved by the finite difference method technique with the Picard iteration scheme combined with the hysteresis model derived by Huang et al. (2005) and the mass conservation control within simulation domain. The results showed that the mixed form had better mass conservation. The present numerical solutions with the hysteresis model were verified by Gillham's experimental data of 1979. The results of the present mixed form numerical approximations with hysteresis effect are better than without hysteresis. In order to raise the accuracy of the soil water Relationship numerical model, hysteresis and mass conservation are important factors in infiltration processes. Copyright © 2008 John Wiley & Sons, Ltd. L'etude presente un modele numerique d'infiltration avec hysteresis et conservation generale de masse pour une application pratique aux sols non satures. Dans les sols non satures, l'hysteresis est un phenomene important dans des processus hydrologiques complexes et il est habituellement ignore dans la simulation de la teneur en eau du sol. L'equation regissant l'ecoulement non sature est l'equation de Richards; il est difficile d'en obtenir les solutions analytiques en raison de la variation dans le temps des conditions aux limites et du changement dynamique de la teneur en eau du sol dans la zone vadose. La solution numerique est resolue par la technique des differences finies avec l'iteration de Picard combine au modele d'hysteresis derive par Huang et al. (2005) et la condition de conservation de masse a l'interieur du domaine de simulation. Les resultats ont prouve que la forme mixte a une meilleure conservation de masse. Les solutions numeriques actuelles avec le modele d'hysteresis ont ete verifiees par les donnees experimentales de Gillham de 1979. Les resultats des approximations numeriques de ces formes mixtes avec l'effet d'hysteresis sont meilleurs que sans hysteresis. Pour montrer l'exactitude du modele numerique de l'eau dans le sol, l'hysteresis et la conservation de masse sont des facteurs importants des processus d'infiltration. Copyright © 2008 John Wiley & Sons, Ltd.
Chuhui Chen - One of the best experts on this subject based on the ideXlab platform.
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a numerical model of infiltration processes for hysteretic flow coupled with mass conservation
Irrigation and Drainage, 2009Co-Authors: Chuhui Chen, Kaiyuan Ke, Mingtsan WangAbstract:The study presents a numerical infiltration model of a hysteretic flow coupled with general mass conservation for practical application to unsaturated soil. In unsaturated soil, hysteresis is an important phenomenon in the complicated hydrological processes, and it is usually ignored when simulating the Relationship of soil water content. The governing equation of unsaturated flow is the Richards equation, and it is difficult to obtain the analytic solutions because of the variation of temporal boundary conditions and the dynamics of change of soil water content in the vadose zone. The numerical solution is solved by the finite difference method technique with the Picard iteration scheme combined with the hysteresis model derived by Huang et al. (2005) and the mass conservation control within simulation domain. The results showed that the mixed form had better mass conservation. The present numerical solutions with the hysteresis model were verified by Gillham's experimental data of 1979. The results of the present mixed form numerical approximations with hysteresis effect are better than without hysteresis. In order to raise the accuracy of the soil water Relationship numerical model, hysteresis and mass conservation are important factors in infiltration processes. Copyright © 2008 John Wiley & Sons, Ltd. L'etude presente un modele numerique d'infiltration avec hysteresis et conservation generale de masse pour une application pratique aux sols non satures. Dans les sols non satures, l'hysteresis est un phenomene important dans des processus hydrologiques complexes et il est habituellement ignore dans la simulation de la teneur en eau du sol. L'equation regissant l'ecoulement non sature est l'equation de Richards; il est difficile d'en obtenir les solutions analytiques en raison de la variation dans le temps des conditions aux limites et du changement dynamique de la teneur en eau du sol dans la zone vadose. La solution numerique est resolue par la technique des differences finies avec l'iteration de Picard combine au modele d'hysteresis derive par Huang et al. (2005) et la condition de conservation de masse a l'interieur du domaine de simulation. Les resultats ont prouve que la forme mixte a une meilleure conservation de masse. Les solutions numeriques actuelles avec le modele d'hysteresis ont ete verifiees par les donnees experimentales de Gillham de 1979. Les resultats des approximations numeriques de ces formes mixtes avec l'effet d'hysteresis sont meilleurs que sans hysteresis. Pour montrer l'exactitude du modele numerique de l'eau dans le sol, l'hysteresis et la conservation de masse sont des facteurs importants des processus d'infiltration. Copyright © 2008 John Wiley & Sons, Ltd.