STUDY OF THE BEHAVIOR OF INHOMOGENEOUS HARMONIC-WAVES IN THEIR DIFFRACTION FROM SIMPLE ROUGH SURFACES

A theoretical model is presented to investigate the diffraction of inhomogeneous waves from a traction-free solid-air boundary having simple periodic profile. It is shown how one can calculate the amplitudes, the angular positions and the exponential decays of the various diffracted orders. The numerical results for a brass-air boundary are compared with the experimental results obtained by Jungman et al.[1]. Our model accounts for the first reflection minimum near the fundamental surface resonance frequency, corresponding to Rayleigh wave generation. This minimum is clearly observed experimentally, but fails to show up in the theoretical results of homogeneous plane wave theory.