Accession Number:

AD0767809

Title:

Fundamental Approximations for the Scattering of Acoustic Waves from a Rough Surface.

Descriptive Note:

Memo.,

Corporate Author:

SACLANT ASW RESEARCH CENTRE LA SPEZIA (ITALY)

Personal Author(s):

Report Date:

1973-08-01

Pagination or Media Count:

31.0

Abstract:

The three main types of approximations used for the scattering of acoustic waves from rough surfaces are discussed Rayleighs Ansatz, the Kirchhoff geometrical-interference approach and the perturbation technique as used by Meecham. In order to compare them they are given in a uniform wave-number representation. They are justified with aid of the Helmholtz integral, which is completely Fourier-transformed. In each approximation the scattering formulae consist of the product of two parts one that is represented by a spectrum of the phase modulations induced by the surface irregularities and another that is a geometrical factor. The corresponding first steps in each approximation are shown to be quite close to each other. The limits of validity are estimated. An interpolation formula unifying the different types of approximations is proposed. Author

Subject Categories:

  • Physical and Dynamic Oceanography
  • Acoustic Detection and Detectors
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE