Experimental and numerical study on a dual-raft wave energy converter with different hinged configurations

This research combines experiments and simulations to evaluate the effects of single and double hinged configurations on dual-raft wave energy converter (WEC) performance. In the double hinged configuration, the floats are bridged by a connecting plate, and a rotational damping PTO (Power take-off) system measures energy capture efficiency. The experimental outcomes reveal a robust correlation between the relative pitch motions and cable tension peaks of both single and double hinged raft WECs, irrespective of float spacing, with the characteristic length of a single float in relation to the wavelength. Further simulations analyzed the differences in energy capture and hinged loads between double and single hinged WECs. This analysis involved adjustments to the PTO rotational damping parameter, the direction of incident waves, float spacing and irregular wave conditions. The findings indicate that the double hinged configuration not only augments the peak capture width ratio but also extends the low-frequency capture band. This configuration exhibits an enhanced wave capture capability at low PTO rotational damping and maintains peak hinged loads comparable to those of the single hinged WEC. Optimal control conditions have demonstrated that the capture efficiency of the double hinged dual-raft WEC surpasses that of its single hinged counterpart, particularly under irregular wave simulations.