Dual effects of a pneumatic breakwater on hydrodynamic characteristics and power generation performance of double offshore floating photovoltaic arrays considering various PV array configurations

Wave loads pose a significant threat to offshore floating photovoltaic systems (FPV). Although pneumatic breakwaters (PB) are effective for wave attenuation, the coupled hydrodynamic interactions between PB-induced aerated flow and double-body floating photovoltaic arrays (DFPV), as well as their effects on power generation, remain insufficiently understood. In this study, physical experiments were conducted to investigate the hydrodynamic characteristics of integrated DFPV-PB systems, including unilateral solar-facing DFPV (DUFPV), roof-type DFPV (DRFPV), and two flexible underwater DFPV models with plate thicknesses of 5 and 10 mm (DFFPV-5 and DFFPV-10). Compared with rigid DFPV, flexible DFPV exhibited smaller sway and heave responses under specific wave conditions, but consistently larger pitch motions. At Tg/d=3.82, PB-induced bubble turbulence effectively reduced sway, heave, and pitch motions, with maximum reductions of 25%, 21%, and 20%, respectively. The electrical performance was further evaluated by establishing a photovoltaic power generation model. DUFPV was suitable for a series configuration, DRFPV required a honey-comb configuration because of uneven irradiance, and flexible DFPV performed best with a series-parallel configuration compared with the series configuration. DUFPV generated the highest power among rigid DFPV, whereas DFFPV-5 performed best among flexible DFPV. PB slightly improved the power output of rigid DFPV, with a maximum increase of only 1‰, and provided enhancement for flexible DFPV by affecting the flexible plate response. In summary, PB provides beneficial dual effects on DFPV hydrodynamics and power generation.