基于水深平均挟沙水流浅水控制方程,引入透水密度系数和阻力项考虑植被群对水流和泥沙运动的影响,建立了充分考虑水流-泥沙-障碍物之间相互作用的耦合数值模型.基于有限体积法离散控制方程,采用Godunov-type中心迎风格式求解单元界面通量.该模型通过水槽洪水实测数据验证,用于研究植被群对溃决洪水和泥沙运动的影响.结果表明:本模型能够模拟溃决洪水演进及底床冲淤变形问题,植被群的存在使得底床冲淤复杂多变,导致植被上游区水位抬升,植被下游区水位明显降低,有助于洪水风险管理.
Based on the depth-averaged governing equations for sediment-laden flows, the coefficient of permeable density and a resistance term are introduced to represent vegetation effects on flow and sediment transport, implementing a fully coupled system among flow, sediment transport, bed and vegetation. The modified governing equations are solved by the finite volume method along with the Godunov-type central upwind scheme for estimating the numerical flux. The model is validated by experimental data of a dam-break flow over mobile beds. Numerical case studies of idealized dam-break flow over mobile and vegetated beds are conducted to shed light on the vegetation effects. It is shown that the vegetation complicates the pattern of erosion and deposition downstream of the dam site, induces water level increase upstream of the vegetated zone and water level decrease downstream. These findings would help flood risk management.