Experimental and numerical study on hydrodynamic performance of a wave energy converter using wave-induced motion of floating body

Abstract

This paper presents results from experimental and numerical investigations on the wave potential extraction of an energy conversion device subjected to regular waves in intermediate water depth. The device is based on a pontoon-type floating breakwater with asymmetric mooring plates. The numerical model is built based on the Navier-Stokes solver coupled with immersed boundary method, volume of fluid method and the mechanics model of energy device. The data obtained in the laboratory investigation suggest that reactive control methods must be employed to optimize the load of the power take off system and maintain the wave energy converter near resonance, which plays an important role in capturing higher wave power. The energy conversion efficiency can reach 14% during experimental runs with only one dynamo installed. Furthermore, by comparing with the experimental results, the applicability of the developed numerical model is demonstrated in predicting the interactions between water waves and the wave power device. With the help of snapshots of water particle velocity field and the wave pressure field from numerical calculation, the flow pattern and external forces from the fluid field can also be estimated. Finally, the effects of mooring angle and the length of floating body on the performance of the energy device are highlighted.

Experimental investigation of a triple pontoon wave energy converter and breakwater hybrid system

“…In addition, Figure 13(a) shows that the displacement of pontoons is amplified by large waves, which in turn reduce the effectiveness of the device in capturing wave energy, especially for lower frequency large waves. This behaviour may help to protect the device during extreme storms [45].…”