Experimental and Numerical Modeling of Dam-Break Flows in Wet Downstream Conditions

Little attention has been paid to the flow dynamics in the reservoir and transitional discharging flows induced by dam break with wet bed conditions at downstream. In this paper, a series of dam-break experiments are carried out in the case of wet bed using non-intrusive imaging technique. The upstream water depth is 0.4 m, corresponding to water depth ratios ranging from 0.05 to 0.4. The numerical simulation is carried out using FLOW-3D with the Large Eddy Simulation (LES) approach. Water depth and flow discharge are obtained experimentally and compared with the results of the numerical model and the Stokers’ solution. It is found that the Stokers’ solution describes the flow regimes well for water depth ratios less than 0.3, but for higher water depth ratios, extra negative waves form in the reservoir and propagate upstream with water surface disturbance. The Stokers’ solution is unable to describe this phenomenon. The internal flow structures show that the flow velocity surrounding the surface trough is larger than that next to the peak in the region affected by the extra negative waves.