Numerical modelling of the spatial distribution of wave overtopping water behind dikes under regular wave action using OpenFOAM

Abstract

The spatial distribution of wave overtopping water behind dikes is a key parameter for assessing the safety zone behind dikes in coastal areas, and it is essential for the safety of pedestrians behind dikes and the placement of critical infrastructure. A 2D OpenFOAM numerical model is validated using experimental data for predicting overtopping discharges and the spatial distribution of wave overtopping water behind a dike. The influences of slope angle, berm, landward ground level, relative structure freeboard, and product of incident wave height and wavelength are studied using a validated numerical model. Numerical model outcomes indicate that the lower slope angle has a critical value that is to be determined by the breaker parameter. Tests were conducted for a range of breaker parameters, including structure freeboard, and empirical-based predictive equations were derived for overtopping events under different wave conditions. We also found that the extent of the hazard area due to wave overtopping is significantly reduced when the landward ground level is negative. The findings of this study provide data and predictive formulas for assessments of the hazard zones behind the dikes and indicate the capability of numerical models in the design and safety assessment of dikes.