Wave energy capturing of an offshore stationary platform equipped with three oscillating wave column devices

Abstract

This paper deals with the hydrodynamic properties of an offshore stationary multi-functional platform consisting of triple oscillating water column (OWC) wave energy converters (WECs). The three OWCs are arranged on the vertices of an equilateral triangle, and one of them is forced to face the incident wave, and is labeled as the seaward OWC. Based on the potential flow theory, a second-order time-domain higher order boundary element method (HOBEM) model was established to investigate the wave energy capturing of this triple-OWCs-platform. It is found that there exists a quarter-cycle phase lag between the surface elevation and the air pressure measured in the chamber of the OWCs. In addition, the wave energy capturing capability of the seaward OWC is found to be improved significantly when the incident wave approaches the platform with an angle of 0 and π/3. Its maximum efficiency can reach up to 97.4% with the optimized device spacing. The averaged efficiency of the three OWCs at the resonant frequency is found to be enhanced when the device spacing is four times larger than the diameter of the OWCs.