An estimation method for acoustic scattering from convex bodies

The problem of plane-wave scattering from a convex body with a soft, rigid or impedance surface is considered. In common with physical optics (PO), the proposed approach exploits the locality property of short-wave scattering. However, in contrast to the PO approximation it considers the curvature of the target and the shadow-side fields. The theory is based on the assumption that each element of integration in the Kirchhoff integral is a patch of a circular cylinder perpendicular to the plane of incidence. Extensive comparisons with exact solutions for spheres of different sizes with constant surface impedances have shown that the approach is more accurate than PO and keeps the PO-comparable simplicity. Although the method is strictly valid for high frequencies, it gives good quantitative results down to resonant frequency range. The approach was also tested on the problem of scattering from a rigid prolate spheroid. An example of application of the technique to a prolate spheroid with a varying surface impedance is presented.