Numerical and experimental investigation of a hinged wave energy converter with negative stiffness mechanism

Abstract

In this study, the performance of a simple and effective negative stiffness mechanism (NSM) from our previous work [1] is investigated by numerical simulation and wave flume experiment. This is one of the few experiments on multiple degrees of freedom (DOF) hinged wave energy converters (WEC) with NSMs. Firstly, the nonlinear governing equations of motions for a multi-modular WEC with NSMs are established based on the Cummins equation. Then, a wave flume experiment for two and three-module WECs is implemented to validate the numerical model and investigate the NSM effect on wave energy capture. Experimental results show that the NSM can enhance the relative pitch response of the raft-type system by up to 60% and thus significantly improve the WEC's capture efficiency. Finally, the wave energy capture performance of the hinged WEC with the NSM in irregular waves is investigated by combining the wave scatter diagram in the South China Sea. The results show that the NSM can enhance the peak of capture width ratio and broaden the capture band at low frequencies.