Reflection, Scattering, and Absorption of Acoustic Waves by Rough Surfaces.

摘要

The first and second moments, i.e. the coherent field and the two-point two-time correlation function, are calculated for the acoustic fields scattered from various rough surfaces. For each surface these yield the reflection, absorption and differential scattering coefficients, as well as an equivalent boundary condition for the coherent field. Renormalized coefficients are constructed to eliminate divergences at grazing incidence. The results are specialized to surfaces which are statistically homogeneous in both space and time, to surfaces which are not moving, to surfaces which are simply or multiply periodic, and to surfaces consisting of randomly placed bosses on a smooth surface. The surfaces considered are slightly rough, moving, soft or hard boundaries, and flat surfaces with random admittances or impedances. The analysis is based on the regular perturbation method or Born approximations. Comparisons with previous results are made. (Author)