Physical and numerical modeling of focused wave interactions with a low mound breakwater

Abstract

Focused waves are a well-known phenomenon that occur in the ocean and can be responsible of offshore structure failure. However, less efforts have been devoted to improve its understanding in the nearshore. This work aims to investigate low-mound breakwater structure stability and functionality associated to transient wave groups. Laboratory experiments were conducted in a wave flume. Free-surface elevation, pressures, and overtopping measurements were employed to validate a numerical model based on the RANS equations. The numerical model predicts the pressures and overtopping with an average relative error of 10 and 8 %, respectively. Subsequently, the numerical model was employed to evaluate the role of the relative structure position with respect to the theoretical focused point. Finally, the physical model results are compared with semi-empirical formulations, finding significant differences for both wave overtopping ( 100 %) and pressure/sub-pressure (88 %) estimates. This work demonstrates that RANS models are an alternative to the classic formulations that failed to predict stability and functionality during these phenomena.