Water waves within a porous medium on an undulating bed

Water wave refraction-diffraction within a porous medium on an undulating s eabed is considered based on lineal wave theory. Using the model of wave-in duced flow within a porous medium and Galerkin eigenfunction expansions, re fraction-diffraction equations for surface waves are derived. With these eq uations, the wave reflection from a porous structure on a sloping beach is investigated and numerical results of reflection coefficients are obtained. A comparison between the present results with those in the literature is m ade for a special case and the agreement is satisfactory. This structure ca n be viewed as an idealized model of rubble-mound seawalls along coastlines . (C) 2001 Elsevier Science B.V. All rights reserved.