A Finite Volume Model for Dam-Break Floods with Wet-Dry Fronts on Non-uniform Grids

In this paper, A second-order accurate, Godunov-type upwind finite volume model on non-uniform grids is developed for simulating dam-break floods. The inviscid fluxes are calculated using the HLLC (Harten-Lax-van Leer-Contact) approximate Riemann solver. A second-order spatial accuracy in space and time are achieved by two-step unsplit MUSCL-Hancock and weighted surface-depth gradient method (WSDGM). A simple but effective method is proposed for modeling wetting and drying. The friction terms are solved by a semi-implicit scheme that can effectively prevent computational instability from small depths and does not invert the direction of velocity components. The applied numerical schemes are validated using three test simulations: dam break wave on a smooth dry bed, partial dam-break simulation and application to dam-break flood in a river. The simulation results show that the proposed model is accurate, robust, and has advantages when it is applied to simulate flows with local complex topographic features or flow conditions.