Surface waves in porous media

Surface waves at the interfaces between a saturated porous medium and vacuum, between a porous medium and fluid, and between two porous media of different structures are studied for the first time. The existence conditions and propagation patterns of surface waves are determined. It is demonstrated that two different surface waves exist at the free surface of a porous medium, three different surface waves exist at the porous medium/fluid interface, and, depending on the densities of solid phases, three or four surface waves exist at the interface between two porous media.