Research on hydrodynamic performance calculation of buoy-chain-sprocket wave energy collection device

Abstract

Buoy-chain-sprocket wave energy collection device is a new type of oscillating buoy wave energy collection device, which has a good application prospect. The calculation method of the hydrodynamic performance of wave energy device (e.g. the first-level average collection efficiency of wave energy) is the core scientific problem of wave energy device, and it is also the theoretical basis for the optimization and control of wave energy device prototype. In this paper, on basis of linear potential flow theory, after the velocity potentials are calculated with eigenfunction expansion method and matching asymptotic expansion method, the frequency-domain wave loads in the heave, surge and pitch directions of the floating body are obtained. And then the motion coordination relationship of the floating body of buoy-chain-sprocket wave energy collection device is used to establish time-domain hydrodynamic motion response equations of the floating body of the device based on the Cummins method. After these equations are solved via the fourth-order Runge-Kutta method, the first-level average collection efficiency of the wave energy device is acquired. In order to further improve the calculation accuracy, the frequency-domain wave-exciting force is calculated by using variable draft depth when the hydrodynamic response of buoy-chain-sprocket wave energy collection device is calculated in this paper. Finally, the reliability of the above calculation method for the hydrodynamic performance of buoy-chain-sprocket wave energy collection device is verified through physical model experiment.