The hydrodynamic performance of a shore-based oscillating water column device under random wave conditions

Abstract

The testing of scale models is crucial if we are to continue the development of wave energy converters. Investigations have examined the interaction of shore-based Oscillating Water Column (OWC) devices with regular water waves that impact the device perpendicularly in flumes or wave basins. However, these simplistic experiments might misrepresent the effectiveness of an OWC system. This study examines the interaction of irregular, oblique, water waves with a shore-based OWC device in terms of its hydrodynamic performance. In a spectral wave basin, a series of experiments were performed on a scale model of a single chamber of the Mutriku Wave Energy Plant. Wave propagation conditions were examined to see their impact on the hydrodynamic performance of a fixed OWC system. The wave amplification factor, hydrodynamic efficiency, non-dimensional air pressure inside the chamber, and non-dimensional water pressures on the chamber walls were evaluated. The results show that when the free surface is close to the front wall lip, the hydrodynamic efficiency increases, while the effect of significant wave height was seen to be more important in the wave amplification. Finally, it was found that the hydrodynamic efficiency under random waves is lower than that in experiments under regular waves reported previously.