Numerical simulation study on the protection mechanism of floating breakwaters for offshore wind turbine foundation platforms

As offshore wind farms are predominantly deployed in nearshore, open sea areas lacking natural protection, the platform structures are directly subjected to wave and wind forces, which can cause seawater run-up or even overtopping, posing serious threats to the safety of superstructures and turbine equipment. Therefore, effectively mitigating the direct impact of marine loads on foundation platforms has become a key issue in ensuring the stability of offshore wind foundations. Among various load-reduction strategies, floating breakwaters have emerged as a promising engineering solution for wave impact mitigation due to their high compliance, flexible deployment, and wide adaptability. In response to this issue, this study employs a high-fidelity numerical wave tank developed in the open-source Computational Fluid Dynamics solver to systematically investigate the efficiency of floating breakwaters in reducing wave loads on foundation platforms. The analysis focuses on the influence of still water depth, incident wave height, platform submergence depth, platform-to-breakwater spacing, and breakwater density, aiming to provide technical insights for the optimized design and protection of offshore wind power infrastructure. The results indicate that the floating breakwater can partially reduce the lateral and longitudinal loads on the foundation platform. Compared to the longitudinal load, the floating breakwater has a more significant attenuation effect on the lateral load, with a larger variation range. When the incident wave height H = 0.13 m (wave height-to-water depth ratio H/d = 0.325), both lateral and longitudinal load attenuation rates reach their minimum values. The submersion depth of the foundation platform significantly affects the floating breakwater's ability to reduce wave loads on the platform. When S/Av = 0, the lateral load attenuation rate reaches its minimum value, and then increases again. The longitudinal load attenuation rate first increases and then decreases, reaching its maximum when S/Av = −0.3. At different distances between the platform and breakwater, the lateral load attenuation rate first decreases, then increases, and then decreases again, reaching its maximum value when Sp/AH = 1. The longitudinal load attenuation rate first increases and then decreases, reaching its maximum when Sp/AH = 2.5. As the breakwater density increases, the lateral load attenuation rate continues to increase. The longitudinal load attenuation rate first increases and then decreases, reaching its maximum value when ρ = 600 kg/m3. These findings highlight the effectiveness and potential of floating breakwaters as a protective measure for offshore wind turbine substructures, providing a valuable reference for their optimized design and engineering deployment. Furthermore, the study demonstrates the critical role of floating breakwaters in mitigating wave-induced loads on offshore foundations and lays a solid foundation for future research on their performance under more complex marine environments, such as combined wave-current and wind-wave conditions.