SOUND-SCATTERING BY SLENDER BODIES OF ARBITRARY SHAPE

Scattering of a spherical wave from a perfectly rigid slender body of arbitrary shape is considered. The point source is assumed to be located in the far field of each body cross section but may be placed in the near field of the target. The problem is investigated theoretically with the matched asymptotic expansions method and an approximate solution is derived for the scattered pressure, which takes into account the curvature of the incident wave front. The presented formalism combines the so-called slender-body approximation and the two-dimensional Kirchhoff theory. It allows a great simplification in the geometrical description of the body surface and leads to a practical method even for bodies of complex shape. In the monostatic case, it is theoretically shown that the obtained solution is asymptotically equivalent to that provided by geometrical optics for a large class of finite scatterers. Lastly, monostatic and bistatic angular distributions are computed for a prolate spheroid in the near and far fields to support the present theory.