Wave power extraction from an integrated system composed of a three-unit oscillating water column array and an inclined breakwater

Addressing the challenges linked to the high Levelised Cost of Electricity in ocean wave energy, the utilization of arrays comprising oscillating water columns (OWCs) emerges as a promising and preferred strategy. In this study, the efficacy of a linear OWC arrayed structure, comprising three identical cylindrical units embedded into an inclined breakwater, was demonstrated by leveraging the Computational Fluid Dynamics technique. The investigation delved into the potential impacts of varying the transverse spacing between the sub-units within the array and adjusting the slope profile. Comparisons were drawn between the integrated system – comprising an arrayed system and an inclined breakwater – and its equivalent embedded into a vertical breakwater under different water depth conditions owing to the influence of the tidal range. The results indicate that superior power extraction emerges when employing a larger transverse spacing, through amplifying the capture width ratio across a broader spectrum of wave frequencies, with a substantial 55.8% increment between the larger and smaller transverse spacing conditions. A moderate slope profile emerges as the favored choice for enhancing performance provided that the transverse spacing is to a larger extent. The advantageous performance of the arrayed system in contrast to the isolated structure, leveraging the principle of the q-factor, becomes more evident, particularly under a moderate slope profile. Additionally, the incorporation of an arrayed system into an inclined breakwater exhibits heightened potential for harnessing wave energy, particularly when stimulated by long-period waves, attributed largely to amplified wave scattering. Conversely, integration into a vertical breakwater excels within the domain of short-period waves.