Hydrodynamic Response of Hybrid FOWC-BBDB Wave Energy Converters Using SPH

To evaluate the longevity and performance of point-absorber wave energy converters (WECs), it is crucial to understand their response to extreme sea conditions.However, data on their hydrodynamic behavior under such stresses is limited.In this study, small-scale experiments using smooth particle hydrodynamics-generated focused waves were performed.These focused waves interacted with a hybrid WEC setup-combining a floating moored oscillating water column (FOWC) and a back-bent duct buoy (BBDB)-and with a point absorber to analyze their mutual effects.Numerical validation against laboratory measurements shows discrepancies in free-surface elevation and pressure of less than 5%, confirming model accuracy.Under hybrid operation, device placement significantly influences efficiency: positioning the system at the front of the wave tank increases the capture width ratio (CWR) by 16.9%, while irregular waves enhance CWR by an additional 7.1% compared to regular waves.Irregular wave conditions generate sway amplitudes up to 40% larger, whereas heave responses of FOWC and BBDB differ by less than 10%.Pitch motions exhibit resonance-driven amplification, reaching 25% above regular-wave levels.Wave-induced forces are dominated by the x-direction component, which exceeds the y-direction component by more than an order of magnitude.The results highlight the enhanced energy capture and dynamic stability of hybrid WEC configurations.