Scattering of sound by sound from Gaussian beams and parametric reception near a reflecting surface.

摘要

A quasilinear solution of the Khokhlov-Zabolotskaya-Kuznetsov equation is derived for the case of two Gaussian beams that intersect at a small angle. In the absence of absorption, a closed-form solution is obtained which is a generalization of the result obtained for parametric receiving arrays by Hamilton, Naze Tjotta, and Tjotta (J. Acoust. Soc. Am. 82, 311-318 (1987)). The solution is used to investigate two problems, (1) the scattering of sound by sound, and (2) the ability of a parametric receiving array to discriminate against multipath interference. In the first investigation, significant levels of scattered sum and difference frequency sound are shown to exist outside the interaction region that is formed by two intersecting primary beams. An asymptotic formula reveals that sum or difference frequency sound is scattered in the approximate direction of k