摘要
基于有限体积法和非结构三角形网格,耦合二维浅水控制方程、泥沙输移方程、河床变形方程建立平面二维溃坝波数学模型。水动力和连续方程均采用浑水方程,考虑了植被对水流、泥沙输移及床面冲淤变化的影响。水动力模型应用二阶精度的Roe格式近似Riemann解计算网格界面的通量,能够精确模拟干湿界面的动边界问题,将静水压力项和植物拖曳力项作为源项反映在动量方程中。应用模型对4个算例进行模拟,并结合实测资料对数值模拟结果进行了验证分析。计算结果表明:本文建立的平面二维溃坝水动力、泥沙耦合数学模型能够准确模拟复杂计算域的溃坝水流演进及床面变形问题。通过对有植被算例的模拟分析发现,滩地种植植物能减少植被区的流速和溃坝波对下游河床的冲刷,但同时也会降低有植被区河道的泄洪能力,导致洪水在上游区水位提升。
Based on the finite volume method and unstructured triangular mesh, a depth-averaged 2D mathematical model for dam-break flows on erodible beds has been developed by coupling the shallow water equations, sediment transport equation, and bed evolution equation. This model adopts the momentum and continuity equations for turbid water considering vegetation effects, sediment transport and morphological changes, and uses a Roe solver and approximate Riemann solutions to calculate the grid face fluxes, which is able to capture dry-wet moving fronts with second-order accuracy. The hydrostatic pressure and the vegetation resistance are put into the source term of momentum equation. The model was verified against four cases of the laboratory measurements documented in the literature, and the calculations agree well with the measurements. The verification shows that the model is able to simulate the evolvement of dam-break flows and the deformation of bed morphology on a complex computational domain with good accuracy. Simulations of the vegetation cases show that the vegetation on a shoal can reduces the velocity of dam-break flows and the erosion on the downstream bed but it also reduces the local flood discharge capacity, which leads to a certain rise in the upstream water level.
出处
《水力发电学报》
EI
CSCD
北大核心
2015年第12期73-83,共11页
Journal of Hydroelectric Engineering
基金
大连市科学技术基金项目(2013J21DW009)
辽宁省自然科学基金优秀人才培育项目(2014020148)
辽宁省高等学校优秀人才成长计划项目(LJQ2013077)
国家重点基础研究发展计划项目(2013CB430403)
关键词
水力学及河流动力学
溃坝水流
有限体积法
Roe格式
植物作用
泥沙输运
hydraulics and fluvial dynamics
dam-break flow
finite volume method
Roe scheme
vegetation effect
sediment transport
