围堰溃决的数值模拟

推导了用于模拟围堰溃决的DIF方程，采用非规则网格有限体积法和显式MacCormack预测-校正数值方法求解该方程，建立了模拟围堰溃决数值模型。实例计算结果表明，本数学模型能合理地模拟天然情况下的河道水流、溃堰前的流场以及围堰溃决后溃堰波的沿程传播。此外，采用在导流洞进口局部区域网格上施加负质量源，出口局部区域网格上施加正质量源间接模拟导流洞过流的方法是合理的。因此，本数学模型可作为工具，为围堰溃决对下游河道两岸城镇的洪灾分析及溃堰预案的制定提供科学依据。

Numerical simulation on cofferdam breach

A 2-D Depth-Integrated Flow(DIF) equation is derived for simulating the generated wave from cofferdam breach,and then a numerical model is established with the irregular body-fitted mesh finite volume method and the explicit MacCormack predictor-corrector method.The case simulation shows that the flow field before the breach and the water wave propagation along the flow-course after the breach can be reasonably simulated by this mode.Furthermore,a feasible method for indirectly simulating the overflow is to apply the negative mass source to the mesh for the local area of the diversion tunnel intake while apply the positive mass source to the mesh for the outlet area .The research result given herein provide a scientific basis for analyzing the impact of the flood disaster from the cofferdam breach on the downstream region and making the emergency provision on prevention of flood disaster from the cofferdam breach.