Two-dimensional shallow hydrodynamic model based an adaptive structured grid

This paper presented an adaptive structured grid-based two-dimensional Godunov type finite-volume numerical model for unsteady shallow water flow,which can locally enrich and coarsen grids,and balance computation efficiency with solver accuracy.Conserved variables of water stage and water depth were reconstructed at the same time to define a uniquebottom of each cell interface.The HLLC approximate Riemann solver was adopted to calculate interface fluxes.Overall second order accuracy in space and in time was achieved by limiting gradients and using second order Runge-Kutta(RK2).Bed source term was central discretization and extra flux term was added to obtain a well-balance scheme.Meanwhile the friction source term was treated in a semi-implicit way to reduce problems associated with numerical instabilities.Finally the presented model was validated by three benchmark tests and the results indicated that the model is well-balance,capture steep fronts well and simulate on complex topography stably and accurately.