Study of dam-break flow over a vegetated channel with and without a drop

Abstract

Abstract The development of catastrophic floods triggered by a dam failure is influenced by the river's bed nonuniformity, infrastructure, and vegetation in the main channel or floodplain. This study examined the effects of the presence of a drop and its direction in a vegetated channel on flow characteristics during dam failure. A CFD package was used for all dam break flow simulations. Using experimental data from the literature, a sensitivity analysis of the fluid cell size and turbulence models were performed. Then, the model was used to predict the flow characteristics during a dam break over the vegetated channel with positive, negative, and no drops. The results showed that the model reproduced with high accuracy the evolution of the flow during a dam break in the presence of an obstacle and transitions, as well as variations in flow velocity. The presence of a drop, its height and direction, and vegetation significantly changed the reservoir discharge, hydrograph in the downstream channel, flow velocity values, location of the inflection points, density, and eddy evolution.