Hydrodynamic Performance and Wave Attenuation Mechanism of a Single-Ring Floating Breakwater with Internal Compartmentalization and Ballasted Water

ABSTRACT: A three-dimensional, two-way coupled fluid–structure interaction (FSI) numerical model was established to investigate the hydrodynamic performance and wave-attenuation mechanism of a water-ballasted single-ring floating breakwater with internal compartmentalization. The model couples the CFD wave solver in OpenFOAM with its built-in six-degree-of-freedom rigid-body motion solver and the dynamic mooring solver MoorDyn. It was validated against two benchmark cases comprising physical wave-flume measurements and published numerical results. Four configurations—unballasted, single-compartment, dual-compartment, and four-compartment—were compared under extreme irregular waves, with different incident-wave headings considered for the compartmentalized configurations. The analysis focused on wave transmission, transient mooring tension, and the combined effects of annular wave scattering and ballast-water sloshing. The results demonstrate that the four-compartment configuration provides the strongest wave attenuation, whereas the dual-compartment configuration achieves a better balance between wave-attenuation performance and mooring-load distribution.