An investigation of the characteristics of dam-break flood in a confluence channel based on the lattice Boltzmann method

摘要

In this study, we use a lattice Boltzmann method with a multi-relaxation-time model to simulate dam-break flooding in confluence channels with four confluence angles. Compared with physical experiment, the simulation proves reliable. We analyze the influence of the confluence angle on the propagation of dam-break flood. The stage hydrograph at the confluence area can be divided into four stages: before the wavefront reaches—rising rapidly—falling gradually—planarization with periodic fluctuation. The water depth of the measuring points in the confluence area is influenced by two factors: the confluence angle and the distance from the measuring point to the first impact point. The results demonstrate that the backwater effect of the confluence is enhanced at higher confluence angles. As the confluence angle increases, the first impact point moves upstream. Moreover, there is a strong backwater effect close to the first impact point, resulting in superelevation mainly occurring in the confluence area.