Influence of the shape of a buoy on the efficiency of its dual-motion wave energy conversion

A procedure is proposed for the geometric design of the buoy of a single-body wave energy converter (WEC) based on the characteristics of incident waves. The effect of the buoy shape on its hydrodynamic performance and the absorption efficiency of WEC model is considered. The model absorbs the wave energy through the dual motion (heave and surge) of the buoy. In order to compare the dynamics of various buoys in waves, a set of requirements is proposed to create identical conditions. Three groups of buoy geometry, including conical, spherical and unusual geometry are considered. The changes in the hydrodynamic parameters of the buoy due to the buoy shape variations are studied to clarify the effect of these changes on the efficiency of the WEC model. The obtained results show that increasing a ratio of hydrodynamic coefficients of the buoy, increases the produced power regardless of the wave frequency. Also, an appropriate shape for the buoy can raise the WEC model performance from suboptimal mode to optimal mode and would also lead to a significant increase in the absorbed power and efficiency. (C) 2020 Elsevier Ltd. All rights reserved.