Scholte Wave Diffraction by a Periodically Rough Surface

Abstract

Bulk wave reflection and diffraction in an infinite medium or plate have been studied for a long time. In a liquid medium, a bulk wave impinging on a plate, with velocity C_f, may generate Rayleigh or Lamb waves. A wave with phase velocity c may be generated, under an angle β (with the normal to the interface) only if the equation (1) C_f = c·sin(β) is satisfied; so the Scholte-Stoneley wave whose velocity is slightly less then C_f for usual solid mediums, may not be generated. However if engraved by a periodical grating a solid substrate may generate waves not satisfying equation (1); on thick substrates [1] and plates [2] part of the incident wave energy is considered to be converted in a Scholte-Stoneley wave, though such a wave has never been observed.