A nonlinear shallow water model simulating dam-break flow over complex downstream beds using (b, s) coordinate

Abstract

Under the current abnormal meteorological conditions, urban flood flow simulation is an efficient problem in disaster prediction calculations for every country, especially those significantly impacted by climate change, such as Vietnam. This article presents the development of a numerical model simulating flow after a dam break on complex downstream beds, with high applicability in urban flood forecasting. The numerical model uses the shallow water nonlinear equations employing the (b, s) coordinates and has the advantage of being simple but effective in simulating
incompressible flow phenomena. The hybrid finite volume-the finite difference method and the explicit three-stage, third-order Runge-Kutta method are used to discretise the governing equations in space and time, respectively. The numerical model is validated with results from analytical models and physical models for the problem with a simple downstream bed. For complex downstream bed cases, the model accurately simulates flow velocity and flow depth for both hump and rough inclined beds.