Numerical modelling of overtopping flow velocity and layer thickness at the waterside edge of the dike crest

The overtopping flow velocity and layer thickness are closely related to the stability of coastal structures. Some empirical formulas are available for estimating the overtopping flow velocities and layer thicknesses. However, these empirical equations were derived based on experiments where only limited amount of wave conditions and dike configurations (mostly smooth straight waterside slopes) were tested. Therefore, the extrapolation of existing empirical equations to cases that are outside of the applicable ranges remains uncertain. Numerical modelling has become an important complementary tool to physical experiments. In this study, we developed a 2DV numerical model based on the OpenFOAM framework to simulate the overtopping flow velocity and layer thickness at the waterside edge of the dike crest. This model is validated by comparing the modelled overtopping flow parameters with the measured ones from physical experiments. The model validation shows that the 2DV OpenFOAM model is capable of predicting the overtopping flow parameters with a low probability (2%) of exceedance reasonably well although the overtopping layer thickness is slightly overestimated.