Numerical modeling of 2-D shallow water flow with complicated geometry and topography

An unstructured finite-volume numerical algorithm is proposed for solving the 2-D shallow water flow equation with complicated geometry and topography.The Roe's approximate Riemann solver is used in the calculation.The characteristic decompose method is applied to deal with the term of bed slope source in the equation,so that the flux can be balanced and the schemes are harmonious.The implicit and semi-implicit methods are used to calculate the friction source terms and enhance the stability of calculation.The validity of the proposed modeling method is verified by two numerical examples.The calculation result of a river section in Guangxi Province,China,is in good agreement with the physical model test data.