Hydrodynamic performance of trapezoidal pendulum wave energy converter

Based on the potential theory, hydrodynamic performance of trapezoidal pendulum wave energy converter was studied by applying the frequency domain method. It is shown that the natural period for a fixed pendulum wave energy converter is relatively long. And the wave energy conversion efficiency is smaller because the radiation damping near the natural period is very small. In linear theory, the nonlinear drag damping is often neglected during studying wave energy converters, the maximum wave energy conversion efficiency is achieved when the natural period of the converter is equal to the wave period and the power take-off damping is equal to radiation damping. As a ship rolling motion, for trapezoidal pendulum wave energy converter, the nonlinear drag damping must be taken into account, so the effect of the nonlinear drag damping on the optimum power take-off damping has to be analyzed. The influence of power take-off damping on the motion amplitude and conversion efficiency are also analyzed.