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

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• 作者：Ming-liang ZHANG ((张明亮))^a ; ^{zhmliang_mail@126.com" class="auth_mail" title="E-mail the corresponding author}Author Vitae ; Yuan-yuan XU ((许媛媛))^a ; Yang QIAO ((乔洋))^a ; Heng-zhi JIANG ((姜恒志))^b ; Zhong-zhe ZHANG ((张钟哲))^a ; Guo-sheng ZHANG ((张国胜))^a
• 关键词：finite volume method ; Harten-Lax-Van Leer (HLL) approximate Riemann solver ; sediment transport ; vegetation effect
• 刊名：Journal of Hydrodynamics, Ser. B
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：28
• 期：1
• 页码：23-32
• 全文大小：2332 K

文摘

The purpose of this study is to establish a depth-averaged 2-D hydrodynamic and sediment transport model for the dam-break 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.