Wave energy attenuation by drifting and non-drifting floating rigid plates

Abstract

Abstract Computational Fluid Dynamics (CFD) is used to numerically simulate the viscous air-water flow around a thin rigid floating plate subjected to surface waves, with the aim to improve the understanding of dissipative mechanisms in drifting and non-drifting conditions. CFD model is validated by comparing the obtained results against previously published data of Nelli et al. (2017). It is shown that the energy of the waves is dissipated by the water flow over both upper and lower surfaces of the plate. The dissipation increases as a function of steepness of incoming waves. On the upper surface of the non-drifting plate, overwash contributes to dissipation of the energy of steep waves, while this effect is slightly smaller when the plate is moving freely. Simple equations are used for estimating the overwash height and energy fluxes, which are found to be in fair agreement with the present CFD simulations. The energy dissipation due to the shear stresses under the surface of the plate is seen to be higher when the body is drifting in the longitudinal direction. Equations for the energy dissipation under the plate are also formulated, and are observed to follow the results of the present CFD simulations.