Numerical investigation of the impact of a dam-break induced flood on a structure

Abstract The flood caused by a dam-break event generally contains a large amount of energy, and it can be destructive to the downstream buildings and structures. In the present study, the evolution of a dam-break flood and its impact pressure on a structure are considered by performing a numerical simulation. A laboratory experiment is first performed to validate the numerical model. Subsequently, simulations are performed to investigate the impact pressure of the dam-break flood on a solitary structure in the downstream region. The flow regime near the structure, temporal variations and distributions of the impact pressure on the structure, and effects of the initial reservoir water depth on the peak pressures are discussed. It is observed that the profiles of the water surface at the cross-section upstream and downstream of the structure are completely different. In addition, the surface velocity distributions are significantly different. The structure suffers a large instantaneous impact pressure when the flood water first contacts the structure, and the value of this pressure can reach 1.5–3.0 times that of the maximum pressure after the first impact. The instantaneous impact pressure is proportional to the initial reservoir water depth. The distribution of the peak pressure acting on the wall on the upstream side of the structure is nonlinear in both the horizontal and vertical directions.