Numerical simulation of dam-break water flow with complex boundary based on governing equations modification

This paper presents a high-resolution two-dimensional finite-volume numerical model based on structured grids for unsteady two-dimensional shallow-water flow over topography with wetting and drying and complex boundary. This model adopts a modified version of the two-dimensional shallow water equations, which correctly balances flux gradient and source terms, and calculates flow flux with Godunov-type finite-volume shock-capturing HLLC schemes. Spatial and temporal accuracy are improved to second order by applying a slope limiter and a prediction-correction method called MUSCL-Hancock, and slope source terms and friction source terms are treated with central difference scheme and fully implicit method respectively. A robust procedure is adopted to efficiently and accurately simulate the movement of wet/dry boundary, and a method of high simulation precision for complex boundary, simplicity of treatment, and high calculation efficiency, is used for calculation of computational boundary. Finally, two tests are used to validate the solver of the model, and the results indicate that the presented model can accurately capture various flow processes and shows good stability and accuracy.