Numerical analysis of wave energy extraction by an inclined detached Oscillating Water Column near a wall

Ocean wave energy constitutes a vast and largely untapped renewable resource, which has driven continuous and in-depth exploration of efficient, robust, and reliable energy conversion technologies. Among the different wave energy conversion technologies, the Oscillating Water Column (OWC) is widely studied for its sustainability and operational flexibility in coastal and offshore environments. The present work focuses on an inclined detached OWC device and evaluates its hydrodynamic response using linear wave theory under both regular and irregular wave conditions in the presence of a rigid wall. For regular waves, the boundary element method is employed to analyse the effects of key geometric parameters, including chamber width, submergence depth, rear and front wall thickness, and wall inclination angle on radiational properties and hydrodynamic efficiency under rigid wall conditions. Under irregular waves, a spectral analysis based on the Bretschneider–Mitsuyasu spectrum is performed to investigate the radiational characteristics and energy efficiency while assessing the comparative analysis that quantifies the influence of a rigid wall on both inclined and vertical OWC configurations. The results highlight that the variations in geometrical parameters directly influence the resonance strength and efficiency bandwidth by altering wave confinement and internal water motion. The rigid wall induces a near-trapped wave formation between the wall and the inclined chamber due to destructive interaction between radiated and reflected waves. The spectral results show that the inclined OWC shows stronger and more stable energy radiation across a range of frequencies compared to the vertical OWC, resulting in a smoother and more consistent efficiency response in realistic sea conditions.