WATER-WAVES ABOVE SUBMERGED POROUS PLATE

Wave motion over a submerged porous plate is studied by the boundary-e lement method based on the linear potential wave theory. The boundary condition at the porous plate is formulated under the assumption that the flow within the porous medium is governed by Darcy's law. The char acteristics of variation of the reflection, the transmission, the loss of energy and the force versus the plate length, the water depth, the incident wavelength, the depth of submergence, and the porosity of th e plate are discussed. It is shown that the reflection and transmissio n coefficients vary periodically as the relative length of the plate t o the incident wavelength increases. Moderately large values of the po rosity of the plate are found to produce the maximum dissipation of th e incident wave energy. It is also demonstrated that a plate with prop er porosity can significantly suppress the reflection and reduce the w ave force acting on it while the transmission can be kept at a low lev el.