Hydrodynamic performance of a submerged hydrofoil wave energy converter (SH-WEC) with latching control mechanism

Abstract

Ocean wave energy is recognised as a promising alternative renewable energy source, reflecting the increased demand seen in recent decades. The present investigation emphasises the hydrodynamic performance of a submerged hydrofoil as a heaving wave energy converter (SH-WEC). Initially, the numerical analysis of the SH-WEC in the frequency domain is performed using the Boundary Element Method (BEM) implemented in MATLAB. In frequency domain analysis, the various physical parameters influencing the energy-capturing efficiency of SH-WEC, such as partially reflecting seawall conditions, angle of incident wave attack, depth of submergence, and positioning of SH-WEC from the seawall, are investigated. The investigation revealed that the presence of a fully reflecting wall substantially improves SH-WEC performance by about 70.55% compared with the open domain. Furthermore, the Cummings equation extends the frequency domain results to time domain analysis. The primary objective of conducting a time-dependent evaluation is to introduce a latching control mechanism designed to enhance the device's power extraction capability without altering the shape and size of the SH-WEC. The comparison between the latched and unlatched SH-WEC reveals that the SH-WEC's enhanced response and the instantaneous and mean power are assessed both with and without the implementation of a control mechanism. The latching duration is vital in the WEC's response and power enhancement. With an optimal latching duration yield, the displacement of SH-WEC improves by up to 62.5%, and the mean power increases to 936.4 W, compared to the pre-latching mean power of 230.3 W in open domain conditions.