A WDM method on a generalized curvilinear grid for calculation of storm surge flooding

In this paper, the wet-dry grid point method (WDM) with generalized curvilinear computation grids is introduced with the aim of presenting a kind of effective numerical model for real-time forecasting of storm surge flooding. To realize this general WDM method, generalized 2-D shallow sea dynamic equations in curvilinear co-ordinates are derived, and the contravariant components of the velocity vector are employed for easily realizing boundary conditions and making the wet-dry point judgement criterion more reasonable. As the generalized equations are not limited to a specific co-ordinate transformation, a self-adaptive grid generation method, which optimizes simultaneously grid smoothness, orthogonality and variation in cell volumes, is then proposed to meet the needs of WDM with varying spacing grids. The paper also provides a numerically stable difference scheme and this scheme is proved accurate by the verification calculation of observed storm surge.