洪水与风暴潮共同作用下的溃堤洪水一维、二维耦合模型及应用

为了解决复杂条件下河道洪水漫堤、溃堤和潮水倒灌的问题,建立了在洪水和风暴潮共同作用下的天然河道漫溃堤洪水在防洪保护区的一二维水动力耦合模型。在兼顾计算效率和精度的基础上,分区剖分网格,设置合理的网格面积;根据植被和地物的不同,分区设置糙率;通过宽顶堰的方式将河道一维模型和防洪保护区二维模型进行侧向耦合;采用基于侵蚀的渐变溃破坏方式模拟河道溃堤过程,实现了河道上游发生洪水和下游遭遇外海风暴潮的复杂情况下精细化模拟。实例研究表明,所建模型可灵活处理复杂多变的水力条件,模拟结果合理可靠,可为防汛部门制定决策提供有力的科学依据。

A 1D-2D coupled model of the dam-break flood under the joint action of flood and storm surge and its application

In order to solve the problems of flood overflow, dam break, and back flow of tidal water in river channels in complex conditions, in this paper, we developed a one- and two-dimensional coupled hydrodynamic model to simulate the overflowing and dam-break flood from natural river channels under the joint action of flood and storm surge in a flood-control protection area. Taking into consideration both computational efficiency and precision, we generated grids of different zones, and set a reasonable grid area. According to different vegetation types and surface features, we set different roughness for different zones. We coupled the one-dimensional model of the river channel and the two-dimensional model of the flood-control protection area through the broad-crested weir, used the erosion-based gradual collapse method to simulate the dam-breaking process of the river channel, and realized fine simulation in the complicated situation with flood in the upper reaches of the river and storm surge in the lower reaches. The case study showed that this model can flexibly deal with complicated and volatile hydraulic conditions, and can produce reasonable simulation results. It can provide a powerful basis for the decision-making of flood prevention departments.