A numerical investigation of irregular wave overtopping on a 2D fixed overtopping wave energy converter

Overtopping wave energy converters (OWECs) are designed to capture the energy from wave overtopping and transform it into clean and renewable electricity. The present paper numerically investigates irregular wave overtopping on a simplified 2-dimensional OWEC, including the mean overtopping discharge, the distribution of individual overtopping volume, the resultant power harnessing of the OWECs and the transmission coefficient. A numerical wave tank based on the computational fluid dynamic approach is set up using the open-source toolbox OpenFOAM. The model has been successfully validated by comparing the numerical results with the data from our experiments and those available in the literature. The numerical results indicate that the primary factors influencing wave overtopping and extracted power performance of the OWECs are the front slope cot beta (beta denotes the front slope angle) and the non-dimensional freeboard Rc/Hm0, with Rc being the freeboard and Hm0 being the significant wave height. An increase in cot ss and a decrease in Rc/Hm0 lead to a higher overtopping discharge, which enhances the capture width and reduces the transmission coefficient. A Weibull distribution has been adopted to describe the exceedance probability of the individual overtopping volume. Using the proposed predictor, the exceedance probability under most conditions can be well predicted within +/- 30%.