Mono-objective optimisation of floating wave energy converter profile in front of vertical seawall

Abstract

Wave energy converter (WEC) optimisation is essential to increase the hydrodynamic efficiency. To achieve this, the influence of buoy shape parameters on the absorbed energy is study. The buoy shape is optimised to maximise the Capture Width Ratio (CWR). Power recovered by the buoy is determined by a linear potential model and the optimal shape parameters are determined by an evolution strategy algorithm called CMA-ES (Covariance Matrix Adaptation Evolution Strategy). First, the evolution of optimal width and draught for a rectangular case are compared. The presence of a sea wall can influence the buoy performance. A vertical rigid sea wall is considered. It is found that the optimal shape has a lower surface area compared to the buoy in the open sea. The maximum CWR is doubled in the presence of the wall. A method to optimise general buoy shape is presented in this article. A quadrilateral case is chosen to illustrate the primary results. In the considered case, power calculation is performed by a BEM (Boundary Element Method) solver. The results of the case without the vertical wall are reported.