Interaction of gravitational waves with permeable breakwater

Abstract

A method for calculating the parameters of gravitational waves that interact with vertical permeable breakwaters, based on potential theory, has been developed and presented. The wave motion of a fluid was described by the velocity potential that satisfies the Laplace equation. The shape of the wave surface and the components of the velocity vector were determined. Numerical analysis of the influence of permeability of the vertical wall on wave energy adsorption was carried out. The propagation of surface gravitational waves in the linear formulation of problems in a channel with a vertical permeable obstacle was analyzed. The dependence of the wave reflection coefficient as a function of the wave transmission coefficient in accordance with the law of energy conservation was given. Experimental studies have been conducted to determine the features of the hydrodynamic interaction of sea waves and coastal protection structures of the permeable type. The experiments were performed in the laboratory in a wave channel with models of vertical slotted walls of different permeability. Visual and instrumental studies have shown the features of the interaction of the wave field with permeable breakwaters, the formation of reflection and transmission waves through the breakwater. It is established that vertical slotted walls, depending on the permeability, significantly affect the wave field, generate reflected waves and waves passing through the breakwater, as well as lead to a significant dissipation of wave energy. The dependences of the reflection and transmission coefficients of the wave, as well as the dissipation coefficient of the wave energy depending on the permeability of the slotted breakwater and the relative depth of the water area were given. It is shown that with increasing permeability of the breakwater the wave reflection coefficient decreased, and the wave transmission coefficient on the contrary increased. It was found that the reflection coefficient of the wave was increased with increasing relative depth, and the coefficient of wave propagation was decreased. The dissipation coefficient of the wave energy had the maximum value, which was observed for greater permeability of the breakwater, when the relative depth compared to the wavelength was increased.