Hydrodynamics of a dual-chamber OWC wave energy converter coupled with a parabolic coast/breakwater

Abstract

A parabolic coast/breakwater can reflect and concentrate incoming waves, creating a high-density wave energy zone at the focal point, offering a promising approach for enhanced wave energy capture. The critical challenge is to capture the focused wave energy efficiently and safely. Oscillating Water Column (OWC) Wave Energy Converters (WECs) have garnered considerable attention for their straightforward design and robust durability. This study aims to optimize and design a dual-chamber OWC device to maximize wave energy absorption around the focal point. Based on the nonlinear potential flow theory, a time-domain higher-order boundary element method was established to simulate the hydrodynamic properties of a dual-chamber OWC WEC coupled with a parabolic coast/breakwater. In this model, a dimensionless pneumatic coefficient is derived for establishing a nonlinear Power Taken-off (PTO) system of the OWC device. Three OWC models of different sizes are used to validate the accuracy and applicability of the pneumatic coefficient. Further the hydrodynamics of a dual-chamber OWC are analyzed by coupling with a parabolic coast/breakwater. The corresponding results of a single chamber are also shown for comparison. The geometry parameters of the OWC device are optimized for higher wave energy capability. It was found that the introduction of the dual chamber enhances the performance of the OWC device.