3D experimental study of a novel Helmholtz-resonator-based floating breakwater for long-period wave attenuation

In order to address the challenge of insufficient wave attenuation performance of floating breakwater (FB) under long-period waves, this study proposes a novel FB structure based on the principle of Helmholtz resonance and incorporating an hydrofoil-inspired design. The proposed breakwater incorporates a Helmholtz resonator as its fundamental structure, integrated with an hydrofoil configuration, perforation layout, and a mooring system. The design is founded on a comprehensive consideration of multiple wave attenuation mechanisms, including energy dissipation and wave reflection. A series of three-dimensional hydrodynamic model tests were conducted to systematically investigate the wave attenuation performance and motion response characteristics of the proposed breakwater. Furthermore, the hydrodynamic behaviour of the structure under various wave conditions was analyzed. The findings indicate that the innovative breakwater substantially enhances wave attenuation for long-period waves. Specifically, for wave periods ranging from 10 to 15 s, the average wave attenuation efficiency reaches 45 %, while for mid-to-long wave periods of 6–9 s, the efficiency exceeds 55 %. The findings obtained from this study offer significant insights into the design of FBs in long-period wave environments and underscore the practical engineering potential of the proposed structure.