Numerical analysis of the response of an onshore oscillating water column wave energy converter to random waves

Abstract

The main objective of this study is to investigate differences of random incident waves from regular ones in performance of wave energy converters (WEC). A numerical analysis of an onshore oscillating water column (OWC) WEC is carried out by means of the FLUENT® software, which is based on Reynolds - Averaged Navier-Stokes equations. Analyses of the efficiency of an onshore OWC device with similar characteristics of the Pico’s plant and equipped with a Wells-type turbine, located at a 10 m deep flume, subjected to random waves with TMA spectrum and regular waves are shown. The resonance occurs at an energy period T ¼ 8.6 s with an efficiency of 62% for a root mean square wave height Hrms ¼ 1 m in random waves, while it is observed at T ¼ 7.1 s with 84% of efficiency for H ¼ 1.00 m in regular waves. Differences between efficiencies of regular and random waves are significant up to around the resonant period. This study showed that the use of random incident waves is fundamental to obtain more real results of analyses of onshore OWC device performance, even considering their requirement of high simulation time.