Numerical simulation of flow and bed morphology in the case of dam break floods with vegetation effect

• Published in: Journal of hydrodynamics. Series B Vol. 28; no. 1; pp. 23 - 32
• Main Author: 张明亮 许媛媛 乔洋 姜恒志 张钟哲 张国胜
• Format: Journal Article
• Language: English
• Published: Singapore Elsevier Ltd 01.02.2016; Springer Singapore
• Subjects: Channels; Computational fluid dynamics; Engineering; Engineering Fluid Dynamics; finite volume method; Fluid flow; Freshwater; Harten-Lax-Van Leer (HLL) approximate Riemann solver; Hydrodynamics; Hydrology/Water Resources; Mathematical analysis; Mathematical models; Numerical and Computational Physics; Sediment transport; Simulation; Vegetation; vegetation effect; 动量方程; 数值模拟; 植被效应; 水动力模型; 浅水方程; 溃坝洪水; 运输模型; 非结构化网格; vegetation effect; sediment transport; finite volume method; Harten-Lax-Van Leer (HLL) approximate Riemann solver
• ISSN: 1001-6058; 1878-0342
• DOI: 10.1016/S1001-6058(16)60604-2

The purpose of this study is to establish a depth-averaged 2-D hydrodynamic and sediment transport model for the dambreak flows with vegetation effect. The generalized shallow water equations are solved using an explicit finite volume method with unstructured quadtree rectangular grid, and in the hydrodynamic model, a Harten-Lax-Van Leer（HLL） approximate Riemann solver is used to calculate the intercell flux for capturing the dry-to-wet moving boundary. The sediment transport and bed variation equations in a coupled fashion are calculated by including the bed variation and the variable flow density in the flow continuity and momentum equations. The drag force of vegetation is modeled as the sink terms in the momentum equations. The developed model is tested against lab experiments of the dam-break flows over a fix bed and a movable bed in vegetated and non-vegetated channels. The results are compared with experimental data, and good agreement is obtained. It is shown that the reduced velocity under vegetated conditions leads to a decrease of the peak discharge and a rise of the water level of rivers and also an enhancement of the sediment deposition.