Acoustic scattering by parameterized concave surfaces using an implementation of the Kirchhoff Integral Method

EDMUNDO LAVIA; RUI MARQUES ROJO

Congreso; 22nd International Congress on Acoustics 2016; 2016

The International Commission for Acoustics (ICA) and the Ibero-american Federation of Acoustics (FIA)

The scattering of sound waves that propagate in the ocean is mainly due to different types of inhomogeneities within seawater. This physical process is of vital importance for its wide range of applications in fisheries, oceanography, ecology and marine detection. This work addresses the calculation of the scattered field by concave objects using the Kirchhoff Integral Method. It mainly consists in solving Green?s Integral Formula and applying the  Kirchhoff approximation (i.e. the surface of the object is partitioned into insonified and shadow regions; the total field and its normal derivative in the insonified region are assumed to be equal to the incident field and its normal derivative, respectively, while they are assumed to be negligible in the shadow region). The well-studied case of convex scatterers has a quite straightforward solution whereas the concave case is more cumbersome. In this work an algorithm is presented to handle the interaction of plane acoustic waves with a parameterized scatterer of arbitrary concave shape. Inorder to verify the numerical results, comparisons with the exact high-frequency far-field solution provided by a collocation method are presented for a 2D object. Additionally, the algorithm is applied to a 3D torus insonified from different incidence directions.