Effect of Different Raft Shapes on Hydrodynamic Characteristics of the Attenuator-Type Wave Energy Converter

A numerical simulation method based on CFD has been established to simulate the fully coupled motion for an attenuator-type wave energy converter (WEC). Based on this method, a detailed parametric analysis has been conducted to investigate the design of the rafts. The effects of different parameters (wave parameters, structural parameters and PTO parameters) on the hydrodynamic characteristics of the attenuator-type WEC were studied in detail. The results show that in terms of wave parameters, there is an optimal wave period, which makes the relative pitching angle amplitude of the WEC reach the maximum, and the increase of wave height is conducive to the relative pitching angle amplitude of wave energy. Under different wave conditions, the relative pitch angle of the parallelogram raft device is the maximum. In terms of structural parameters, the parallelogram attenuator-type device has the optimal values in different relative directions, different distances and different apex angle, which makes the relative motion amplitude of the device reach the maximum, and the spacing and the apex angle have influence on the motion frequency of the device, while the relative direction has almost no influence on it. In terms of PTO parameters, there is an optimal damping coefficient, which makes the power generation efficiency of the WEC reach the maximum. The research results provide a valuable reference for future research and design of the attenuator-type WEC.