Study the effect of obstacle arrangements on the dam-break flow

Infrastructure, including roads, bridges, and municipal facilities, act as barriers to the downstream propagation of flood waves following a dam failure. The aim of this work is to investigate the effects of the obstacles and their arrangement on the evolution of flood waves during a dam breach using a numerical approach. The obstacles were arranged in two arrangements (triangular and inverted triangular) perpendicular to the flow direction in the downstream channel. Wave propagation during dam failure and flow dynamics were modelled by the finite volume method (FVM) using a CFD package. The evolution of the free surface of the dam breach was traced using the volume of fluid (VOF) method. However, the uncertainty of the model was evaluated using a sensitivity analysis with respect to the mesh resolution and turbulence models. The turbulence characteristics were captured by large-eddy simulations (LES) after validating the model using experimental data from the literature. The results show that the model can efficiently reproduce the wave development during a dam failure and the flow characteristics. The arrangement of the obstructions played an important role in the development of flow around the obstructions through the downstream channel. In this direction, the transitional flow regime, resultant forces in reservoir, and three-dimensional flow velocity around the obstacles were predicted for different arrangements.