Semi-analytical study on an integrated-system with separated heaving OWC and breakwater: Structure size optimization and gap resonance utilization

Abstract

To complement the topic on the integration of Oscillating Water Column (OWC) device with breakwater structures, a novel integrated system composed of an offshore heaving OWC device and a floating stationary breakwater with a certain length of gap between each other is proposed. Under the framework of potential flow theory, corresponding theoretical model is established and solved by decomposing the boundary-value problems into one wave scattering component and two radiation components. Apart from the examinations concentrating on the influences from the geometrical configuration of the breakwater, the gap distance between the OWC device and the breakwater is changed in a broad range to identify its effects on the interested hydrodynamic performance. It is found that for a specific wave frequency, when the gap distance is well-tuned against the wave length to satisfy the condition of sloshing mode happening inside the gap, power extraction efficiency is much likely to achieve its maximum extent. In this way, the optimization in terms of gap distance is proved to be effective in enhancing wave power capturing within a wider range of wave conditions.