Two-dimensional numerical study of the wave/current-seabed-overtopping breakwater for energy conversion interaction

In recent decades, overtopping breakwater for energy conversion (OBREC) has attracted much attention due to its short investment payback period, providing new development directions for commercial application of wave power extraction. Currently, existing study on OBREC is still in its infancy, focusing mainly on assessing power generation efficiency and ignoring structure stability. Therefore, a program for simulating wave/current-seabed-OBREC interaction is developed in this study to analyze the stability of OBREC. Results show that a relationship between wave reflection coefficient and relative water depth exists, and a S-shape curve fits well to different wave parameters, which is useful for practical engineering. Reservoir overturning may occur due to wave-induced large seepage force on base. Among these, the current velocity has the greatest impact on the vertical force acting on base. When current velocity increases from 0 to 3 m/s, the vertical force increases by approximately 500 %. Analysis reveals that the seabed pore pressure decreases from front toe to back toe of breakwater. Furthermore, momentary liquefaction mainly occurs at the front toe, and the current velocity also has the most significant impact on the liquefaction extent. When u c = 3 m/s, the maximum liquefaction depth is four times of that for the wave-only case.