Experimental investigation of the breakwater consisting of an array of cylindrical oscillating water column devices: Hydrodynamic characteristics and wave energy conversion

Abstract

Integrating OWC into breakwater is a win-win program that accomplishes function expansion and cost-sharing. In the present study, a non-intercepting breakwater, integrated with an array of cylindrical OWCs aligned linearly with a certain distance, is proposed and experimentally studied, emphasizing the hydrodynamic characteristic and wave energy conversion. The superiority of the proposed OWC-type breakwater in coastal protection is affirmed by comparing hydrodynamic experiments of three specific configurations. The effects of the OWC array's porosity, wave height, and draft on the hydrodynamic characteristics and wave energy conversion are investigated in detail. Under an array layout, the hydrodynamic interaction between devices contributes significantly to the hydrodynamic response of OWC. When the cylindrical OWC array has a porosity of 0.2 to 0.6, the wave energy conversion is improved in terms of both a larger peak efficiency value and a broader efficient frequency bandwidth. A smaller porosity can result in a larger second-order wave component in the wave at the center of adjacent OWC devices. In addition, the wave transmission can be effectively suppressed by decreasing the OWC array's porosity or increasing the device's draft. In practice applications, the OWC array's porosity needs to be determined flexibly according to the project objectives.