A coupled unsaturated-saturated water flow numerical model was developed. The water flow in the unsaturated zone is considered the one-dimensional vertical flow, which changes in the horizontal direction according to ...A coupled unsaturated-saturated water flow numerical model was developed. The water flow in the unsaturated zone is considered the one-dimensional vertical flow, which changes in the horizontal direction according to the groundwater table and the atmospheric boundary conditions. The groundwater flow is treated as the three-dimensional water flow. The recharge flux to groundwater from soil water is considered the bottom flux for the numerical simulation in the unsaturated zone, and the upper flux for the groundwater simulation. It connects and unites the two separated water flow systems. The soil water equation is solved based on the assumed groundwater table.and the subsequent predicted recharge flux. Then, the groundwater equation is solved with the predicted recharge flux as the upper boundary condition. Iteration continues until the discrepancy between the assumed and calculated groundwater nodal heads have a certain accuracy. Illustrative examples with different water flow scenarios regar.ding the Dirichlet boundary condition, the Neumann boundary condition, the a.tmospheric boundary condition, and the source or sink term were calculated by the coupled model. The results are compared with those of other models, including Hydrus-lD, SWMS-2D, and FEFLOW, which demonstrate that the coupled model is effective and accurate and can significantly reduce the computational time for the large number of nodes in saturated-unsaturated water flow simulation.展开更多
This paper discusses the analytic solutions of the diffusion equation for the movement of water in unsaturated soil. Firstly, according to the experience relation between the diffusivity 'D(theta)' and water c...This paper discusses the analytic solutions of the diffusion equation for the movement of water in unsaturated soil. Firstly, according to the experience relation between the diffusivity 'D(theta)' and water content in soil 'theta', and through variable substitution, the original diffusion equation is converted into the form easy to solve. Then, the variables separation method together with the Boltzmann transform method is used to find out the solution of the new partial differential equation. so the analytic function of 0(x, t) is obtained, which is verified by the experiment of water flow through unsaturated soil.展开更多
基金supported by the National Basic Research Program of China (Grant No. 2010CB428802)Scholarship Award for Excellent Doctoral Students granted by Ministry of Education+1 种基金the Fundamental Research Funds for the Central Universitiesthe Ph. D. Candidates' Self-research Program of Wuhan University in 2008
文摘A coupled unsaturated-saturated water flow numerical model was developed. The water flow in the unsaturated zone is considered the one-dimensional vertical flow, which changes in the horizontal direction according to the groundwater table and the atmospheric boundary conditions. The groundwater flow is treated as the three-dimensional water flow. The recharge flux to groundwater from soil water is considered the bottom flux for the numerical simulation in the unsaturated zone, and the upper flux for the groundwater simulation. It connects and unites the two separated water flow systems. The soil water equation is solved based on the assumed groundwater table.and the subsequent predicted recharge flux. Then, the groundwater equation is solved with the predicted recharge flux as the upper boundary condition. Iteration continues until the discrepancy between the assumed and calculated groundwater nodal heads have a certain accuracy. Illustrative examples with different water flow scenarios regar.ding the Dirichlet boundary condition, the Neumann boundary condition, the a.tmospheric boundary condition, and the source or sink term were calculated by the coupled model. The results are compared with those of other models, including Hydrus-lD, SWMS-2D, and FEFLOW, which demonstrate that the coupled model is effective and accurate and can significantly reduce the computational time for the large number of nodes in saturated-unsaturated water flow simulation.
文摘This paper discusses the analytic solutions of the diffusion equation for the movement of water in unsaturated soil. Firstly, according to the experience relation between the diffusivity 'D(theta)' and water content in soil 'theta', and through variable substitution, the original diffusion equation is converted into the form easy to solve. Then, the variables separation method together with the Boltzmann transform method is used to find out the solution of the new partial differential equation. so the analytic function of 0(x, t) is obtained, which is verified by the experiment of water flow through unsaturated soil.
