A novel well-balanced scheme for modeling of dam break flow in drying-wetting areas

Abstract

A well-balanced explicit/semi-implicit finite element scheme is proposed for the simulation of dam break flows over complex domains involving wetting and drying. The numerical model is based on the nonlinear shallow water equations in the hyperbolic conservation form. The governing equations are discretized by a fractional finite element method using a characteristic-Galerkin procedure. Firstly, the intermediate increment of a conserved variable is obtained explicitly neglecting the pressure gradient term. And then, the increment is corrected for the effects of pressure once the pressure increment is obtained from the Poisson equation. In order to maintain the “well-balanced” property, the pressure gradient term and bed slope terms are incorporated into the Poisson equation. Moreover, a local bed slope modification technique is employed in drying-wetting interface treatments. The new model is validated against several benchmark tests and laboratory experimental datas related to dam-break flood wave propagation and promising results are obtained.