Finite Volume Method and Riemann Solver for Depth-Averaged Two-Dimensional Flow-Pollutants Coupled Model

A depth-averaged two-dimen sional flow-pollutants coupled model is developed to evaluate impacts of industrial effluents and domestic waste on water environment.Developed in the framework of finite volume method on an unstructured grid,the model transfers 2-D problem in to solving a series of local 1-D problem.It takes the merits of the finited ifference method and the finite element method.The model employs Osher-type approximate Riemann solver to estimate the numerical flux of variables across the interface between cells with high accuracy.The model can be applied to the unsteady and steady stated as well as the subcritical and supercritical flowregimes.The model was examined by several samples with exact solutions.The comparison between computed results and exact solutions demonstrates very good agreement.Finally,the model was applied to water quality simulation in Hanjiang River.The simulated polluted area is matched well with observations.