二维溃坝的数值模拟及其自由液面大变形流动研究

Numerical Simulation of Two-Dimensional Dam Break and Research on Large Deformation Flow on Free Surface

针对溃坝发生后水体会与下游建筑物发生相互作用形成绕射和反射流场,进而改变原始水流的形态、水深以及波传播速度从而导致严重的灾难性后果的情况,文章考虑了单一液体的溃坝问题,采用VOF法构建了相应的二维简化数值模型,分析了不同外形障碍物与溃坝水流之间的相互作用和影响,阐明了溃坝问题中自由液面大变形复杂流动的作用机理。结果表明,不同形状障碍物均能对溃坝水流起到一定的阻碍作用,水体在障碍物的角隅处发生的流动分离现象与该处的坡度密切相关。为了证明本文的数值模拟的可靠性,还给出了闸门抽出与下游带有湿床两种情况的溃坝仿真结果,并将其与试验了进行对比。

In view of the fact that the water body interacts with downstream structures to form diffracted and reflected flow fields after dam break,thus changing the original water flow shape,water depth and wave propagation velocity,which leads to serious disastrous consequences.Considering these circumstances,this paper studies the problem of a single liquid dam break.A corresponding two-dimensional simplified numerical model using VOF method is constructed to study the interaction and influence between obstacles of different shapes and the dam-break flow.And the mechanism of complex flow with large deformation of free surface in dam break is analyzed.The results show that obstacles of different shapes can hinder the flow of the dam break to a certain extent,and the flow separation phenomenon of the water body at the corner of the obstacle is closely related to the slope of the place.The simulation results of sluice gate extraction and dam break downstream with riverbed are also given in this paper to prove the reliability of the numerical simulation.