Title : A quantitative reassessment of damping sensitivity and shape evolution in a PSO-optimized multi-DOF wave energy converter buoy
Abstract:
In order to improve the wave energy capture rate of the buoy of a wave energy generation device, this paper presents a focused quantitative reassessment of previously published simulation and scale-model results for a particle-swarm-optimized, pendulum-type multi-degree-of-freedom wave energy converter (WEC). Firstly, a multi-degree-of-freedom wave energy converter (WEC) coupled to an offshore fixed wind turbine was designed, and the buoy shape was defined by a B-spline curve, generating a five-dimensional shape vector. Then, a numerical model of the multi-degree-of-freedom WEC was established and time-domain numerical calculations were carried out using joint AQWA/WEC-Sim software. On this basis, the particle swarm optimization (PSO) algorithm was introduced to search for the buoy shape corresponding to the maximum wave energy capture under irregular waves. The results show that, as the captured wave energy increases, the buoy shape tends to be flatter with a smaller taper, the buoy draft volume decreases and the wet surface area increases. The fitness function converges to 13.422 kW, 12.132 kW and 12.390 kW under buoy damping coefficients of 0, 5.0×10⁵ Nms/rad and 1.0×10⁶ Nms/rad, respectively. Finally, a wave tank experiment verified that the optimal buoy shape has a better motion response than the conventional cone buoy, confirming the correctness of the proposed buoy shape optimization method. These results support a stronger motion response, but do not by themselves establish a corresponding increase in measured electrical or absorbed power.
