Hydrodynamic performance of a composite polygonal floating breakwater (CPFB): experimental study and CFD simulation

Enhancing the wave attenuation performance of floating breakwaters is critical for the protection of offshore infrastructure and operations. This study introduces a composite polygonal floating breakwater (CPFB) featuring an inclined surface and multiple corners, and evaluates its hydrodynamic performance using integrated physical and numerical modeling. Within the investigated parameter range, the CPFB consistently exhibited lower transmission coefficients than the single box floating breakwater (SBFB) of the same width, with transmission coefficients not exceeding 0.60. The improved performance of the CPFB is associated with its configuration-specific interactions with waves. These interactions intensify vortex generation and wave run-up and reduce downstream wave energy. Although the tested configuration yields smaller structural motions, it results in larger dimensionless mooring forces. Accordingly, a preliminary empirical relationship was developed to estimate the dimensionless maximum mooring force as a function of the wave steepness, relative draught, relative breakwater width and transmission coefficient. For the additional wave-condition cases considered, the assessment errors were within 15%, indicating that this relationship may provide a preliminary reference for estimating the maximum mooring force at the floating body connection under conditions similar to those investigated in this study.