Abstract
In this paper, a cylindrical dual-chamber oscillating water column (OWC) wave energy converter semi-embedded in a coastline or breakwater is proposed. A theoretical model based on linear potential flow theory is developed to evaluate the power absorption performance of the integrated system in the finite water depth. According to the matched eigenfunction expansions, the fluid domain is divided into five sub-domains and unknown coefficients in the diffraction and radiation problems are separately solved by matching the velocity and pressure between adjacent sub-domains. A linear power take-off system considering air compressibility is adopted to connect air volume flux with the chamber pressure. The reliability of this model is assessed by general identities (i.e., far-field relations). Then the model is performed to investigate the effects of wave conditions, draft, breadth and opening angle of the chambers on the wave power extraction. It is shown that the proposed integrated system can improve the total hydrodynamic efficiency in both regular and irregular waves.