Hydrodynamic performance and flow field analysis of a novel floating breakwater hybrid system with an integrated oscillating body

Recently, integrated systems combining floating breakwaters with Wave Energy Converters (WECs) have garnered significant interest for their dual-function potential in coastal protection and renewable energy harvesting. This paper focuses on the fundamental hydrodynamic coupling mechanisms of a hybrid system, where the WEC operates in a passively oscillating mode (without a power take off system). A two-dimensional numerical wave flume based on Smoothed Particle Hydrodynamics (SPH) method is established to investigate its hydrodynamic performance. The results demonstrate that the heave motion of the passive WEC enhances local unsteady flow fluctuations in the narrow-gap region, thereby improving the system’s overall wave attenuation capability. Furthermore, the relative motion between the WEC and the moored breakwater amplifies energy dissipation through the narrow-gap effect. The presence of the WEC effectively transfers and dissipates incident wave energy via its own motion and the induced unsteady flow fluctuations, thereby simultaneously optimizing wave dissipation performance and structural stability.