ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

5aUW13. A unified perturbation approach to volume and roughness scattering.

Anatoliy N. Ivakin

Andreev Acoust. Inst., Shvernika 4, Moscow 117036, Russia

A unified approach is developed to study scattering from a fluid medium with irregularities of two different types: volume inhomogeneities (spatial fluctuations of the compressibility and density) and roughness of the interfaces. The approach treats roughness as a perturbation of the volume acoustic properties in the vicinity of the flat (unperturbed) surface. This permits a description of the scattering problem in terms of a unique integral equation for both types of irregularities. In the case of small roughness, the first iteration of this equation gives results corresponding to the extended Born approximation but provides a new approach for the case of interfaces with large, smooth roughness. As an application, acoustic scattering from a seabed consisting of an arbitrary number of irregular layers with volume inhomogeneities and rough interfaces is considered. [Work partially supported by ONR.]