A two dimensional numerical model for simulation of flood propagation in initially dry bed

摘要

A two dimensional depth averaged numerical model is developed and subsequently applied to simulate flood flow in alluvial rivers with initially dry bed. In the model, Finite Volume Method (FVM) for unstructured mesh with Osher scheme, an approximate Riemann solver, was used to obtain numerical fluxes. In order to obtain second order spatial accuracy, piecewise linear interpolation approach was adopt and the well know "minmod" slope limiter was applied to avoid non-physical oscillation. As a test case, the flood occurred in Nanshahe River, which belongs to Haihe River basin, in the August of 1996 was simulated by the model. Numerical test shows that the simulated water level and the flood propagation process agree well with field observation.