Numerical Study on the Wave Attenuation Performance of a Novel Partial T Special-Type Floating Breakwater

Floating breakwaters (FBs) play an important role in protecting coastlines, marine structures, and ports due to their simple construction, convenient movement, cost-effectiveness, and environmental friendliness. However, the traditional box-type FBs are flawed due to their requiring large sizes for wave attenuation and their overly high level of wave reflection. In this paper, a novel partial T special-type FB with wave attenuation on the surface and flow blocking below the water has been presented. First, the User-Defined Function (UDF) feature in ANSYS Fluent was employed to compile the six degrees of freedom (6-DOF) motion model. A two-dimensional viscous numerical wave flume was developed using the velocity boundary wave-generation method and damping dissipation wave-absorption method, with fully coupled models of the FBs developed. A VOF multiphase flow model and a RANS turbulence model were employed to capture the free flow of gas–liquid two-phase flow. Then, the performance of wave attenuation of the new FB was compared with that of the traditional box-type FB of the same specifications. The simulation results showed that the transmission coefficient of the new FB is significantly lower than that of the box-type FB, and the dissipation coefficient is notably higher, demonstrating excellent performance of wave attenuation, particularly for long-period waves. As wave height increases, the novel FB benefits from its wave attenuation mechanism, with a lower reflection coefficient compared to the box-type FB. Finally, through parametric analysis, some design recommendations of the novel FB suitable for practical engineering applications in deep-sea aquaculture are presented.