A well-balanced two-dimensional numerical model for dam-break flood simulation

A two-dimensional hydrodynamic model is developed to simulate the dam-break flood wave propagation over complex topography. A structured grid and the finite volume method are used for the model development. A central upwind scheme is used to calculate the flux at the interface of computational meshes and the linear reconstruction of flow variables is adopted to achieve the second-order accuracy in space. The bed slope source term and friction term are respectively discretized using a central difference scheme and a semi-implicit method, which can ensure a well-balanced property and the stability of the model. The negative water depth is the key factor affecting the model stability when a dam-break flood simulation is performed on irregular terrains. The new model is able to avoid negative water depths when the Courant number remains less than 0.25. Therefore, the new model is more robust and stable compared to most existing models. The numerical result shows that the model is stable and robust, and has a wide range of application potentials.