Hydrodynamic optimization of a heaving buoy for enhanced wave energy absorption

Abstract

This study presents a hydrodynamic analysis of an optimised heaving buoy for a single-body point absorber wave energy converter (WEC). A conventional deep-draft cylindrical buoy is modified into a composite single-body configuration consisting of three rigidly coupled sections to improve frequency-dependent hydrodynamic performance while reducing structural volume. The proposed buoy is compared with a reference cylindrical buoy adapted from Ruezga (2019). The governing equations are formulated considering added mass, radiation damping, and hydrostatic restoring forces. Numerical simulations are performed in Ansys AQWA under both frequency-domain and time-domain conditions using regular and irregular wave analyses. The results show that the proposed buoy increases peak absorbed power to 58.4 kW, achieving a 6.8% improvement over the reference buoy, together with a 15% broader operational frequency bandwidth. These improvements are achieved with approximately 10% reduction in structural volume while maintaining a simple oscillating system configuration. The findings demonstrate the effectiveness of geometry-based optimisation for improving the hydrodynamic performance of point absorber WECs.