Modelling the impact of a dam‐break wave on a vertical wall

Dam-Break waves arise from the sudden release of the water stored behind a wall, and they cause destruction and losses on nearby areas. Characterisation of the impact force on obstacles is very important for risk assessment. In this work, we performed a series of lock-release experiments to evaluate the wave-induced impact force on a vertical end wall situated some distance from the lock. Laboratory data were used to evaluate the performance of several types of numerical models to predict the wave-induced force on the vertical end wall. The selected models were as follows: the hydrostatic 1D De Saint-Venant model, the multi-layer hydrostatic model and the Navier–Stokes two-phase flow. For the latter two models, both 2D (in the - plane) and 3D simulations were performed. The results show that, independently of the hydrostatic assumption, the 2-D simulations generate nonphysical oscillations which are not present in the measured temporal histories of the pressure and force values. By contrast, the predictions of both 3D numerical models better reproduce the temporal variation of the pressure forces on the end wall. The present study also shows that from a practical point of view, the 1D De Saint-Venant model predicts with sufficient accuracy the impact time and the magnitude of the peak value of the impact force. Therefore, if the use of a fully 3D models is not a feasible option, in terms of a trade-off between computation cost and accuracy, the use of a simple hydrostatic 1D De Saint-Venant model is preferable to a 2D model.