基于非结构网格的分蓄洪区水沙演进数学模型研究

Unstructured Grid Model of Flow and Sediment Evolution in Flood Diversion and Storage Area

基于非结构三角形网格,采用有限体积算法,建立了分蓄洪区水沙演进数学模型。模型网格能很好适应分蓄洪区复杂的边界条件,应用了DEM数字模型插值技术,能快速获取计算域的地形数据,实现了洪水演进过程中泥沙输移和河床冲淤变形的同步模拟。模型中还对网格划分、数值离散、动边界及干河床处理等关键技术进行了研究,并提供了相应的处理方法。该模型在荆江分洪区得到成功运用,较好地复演了1954年分洪过程。洪水计算成果可为分蓄洪区防洪决策与抢险提供参考,分洪闸后最大冲刷深度计算成果可为工程设计提供参考。

Based on unstructured triangular grid and Finite Volume Method,a flow and sediment evolution model in flood diversion and storage area is founded in this paper.One advantage is that the model grids can adapt to complicated boundary conditions well,and the terrain data of the computational domain are obtained quickly by using DEM numerical model interpolation technology.Another advantage is that the sediment transport and riverbed deformation can be simulated synchronously.Key techniques including grid partition,numerical separation,treatments of movable boundary and dry riverbed are studied and the corresponding processing methods are introduced.Furthermore,the model has been applied successfully to the simulation of flood diversion in 1954 in Jingjiang flood diversion and storage area.The calculated flood results can serve as reference for flood control policy-making and flood rescue,and the maximum erosion depth behind the flood diversion gate can provide reference for engineering design.