Diffraction of a non-stationary linearly inhomogeneous acoustic wave which slides off a semi-infinite soft screen

摘要

An exact analytical solution of a new non-stationary scalar diffraction problem is obtained and analysed. A plane acoustic wave with a profile in the form of a delta function propagates along a semi-infinite soft screen. The wave amplitude varies linearly along the wave front. After reaching the end of the screen it "slides" off the screen, generating a diffraction field. A special modification of the Smirnov-Sobolev method is used to find this field. The solution is obtained in the form of an elementary function. It is shown that the sliding wave excites a travelling perturbation that is unlimited along the length of the screen. A similar phenomenon obviously also occurs when elastic waves slide from a cut (crack), which must be taken into account, in particular, in fracture theory. (C) 2015 Elsevier Ltd. All rights reserved.