Dynamic Response Analysis of Pneumatic Floating Breakwater Mounted Wave-power Generation System of Oscillating Water Column

摘要

Ocean wave energy harvesting is still too expensive despite developing a variety of wave energy converter (WEC) devices.For the cost-effective wave energy harvesting,it can be an effective measure to use existing breakwaters or newly installed breakwaters for both wave control and energy harvesting purposes.In this study,we investigated the functionality of both breakwater and wave-power generator for the oscillating water column (OWC)-type wave energy converter (WEC) installed in a pneumatic floating breakwater,which was originally developed as a floating breakwater.In order to verify the performance of the breakwater as a WEC,the air flow velocity from air-chamber to WEC has to be evaluated properly.Therefore,air flow velocity,wave transformation and motion of floating structure was numerically implemented based on BEM from linear velocity potential theory without considering the compressibility of air within the chamber.Air pressure,meanwhile,was assumed to be fluctuated by the motions of structure and the water level change within air-chamber.The validity of the obtained values can be determined by comparing the previous results from the numerical analysis for different shapes.Based on numerical model results,wave transformation characteristics around OWC system mounted on the fixed and floating breakwaters,and motions of the structure with air flow velocities are investigated.In summary,all numerical results are almost identical to the previous research considering air compressibility.Therefore,it can be concluded that this analysis not considering air compressibility in the air chamber is more efficient and practical method.