Abstract
A point absorber wave energy converter (WEC) which converts wave energy into electrical energy with a multi-axis power-take-off (PTO) system is considered here. Previous wave tank trials have proved the ability of the multi-axis WEC to absorb wave power. In this study, the boundary element method (BEM) based software Ansys@ AQWATM was applied to model and analyze the power absorption performance of the multi-axis WEC for a wider range of regular and irregular waves. To verify the numerical model, a laboratory-scale physical model was manufactured and tested. Results show that the multi-axis WEC can absorb more power from the incident regular wave power compared to single-axis WECs and the efficiency reaches up to 45%. It is found that the wave frequency and incident angle significantly influence the amount of absorbed power from different motion modes and PTO axes. Then the numerical model is simulated at 12 nearshore locations in East and South China Sea. The results indicate that the multi-axis WEC can absorb up to 5 kW and the efficiency can reach up to 29% at the most energetic site Shengshan. In addition, considerable differences of mean absorbed power efficiency can be found between sea states.