Gravity wave interaction of fibrillar adhesive floating breakwater proximity to rigid and porous structures positioned at a finite distance from a monotonically decreasing seabed

The influence of proximity rigid and porous structure for mitigating the wave force and excessive motion on the fibrillar adhesive floating breakwater positioned at a finite distance from the monotonically decreasing seabed is investigated under the presumption of linear water wave theory. The objective of the study is to examine various hydrodynamic characteristics associated with wave scattering and radiation, including the added mass and radiation damping coefficients, which pertain to the heave, surge, and pitch motions of the fibrillar adhesive floating breakwater, as well as the vertical force, horizontal force, and moment acting on the fibrillar adhesive floating breakwater across a range of wave and structural parameters. The physical setup is solved semi-analytically by employing the Eigenfunction expansion method and multi-domain boundary element method, and its findings are validated against prior studies. The study reveals that the decrease in the friction coefficient of the porous structure enhances resonant peaks in wave force, moment, added mass, and damping coefficient corresponding to all motions of the fibrillar adhesive floating breakwater. Further, the larger ripple amplitude of the monotonically decreasing seabed alters the pressure distribution and wave kinematics on the fibrillar adhesive floating breakwater. Moreover, the surface elevation is most prominent around structural gaps and the recesses and edges of the step-like front face of the fibrillar adhesive floating breakwater, where constructive interference and partial wave entrapment occur. Thus, by focusing on wave-structure interaction modeling and system-level performance evaluation of fibrillar adhesive floating breakwater, this paper lays a strong foundation for subsequent research that will include parametric studies, material optimization, and large-scale prototype development in diverse coastal applications.