EXTERIOR STABLE DOMAIN SEGMENTATION INTEGRAL-EQUATION METHOD FOR SCATTERING PROBLEMS

This paper is concerned with the development of an exterior domain seg mentation method for the solution of two- or three-dimensional time-ha rmonic scattering problems in acoustic media. This method, based on a variational localized, symmetric, boundary integral equation formulati on leads, upon discretization, to a sparse system of algebraic equatio ns whose solution requires only O(N) multiplications, where N is the n umber of unknown nodal pressures on the scatterer surface. The new pro cedure is analogous to the one developed recently1 except that in the present formulation we avoid completely the use of the hypersingular o perator, thereby reducing the computational complexity. Numerical expe riments for a rigid circular cylindrical scatterer subjected to a plan e incident wave serve to assess its accuracy for normalized wave numbe rs, ka, ranging from 0 to 30, both directly on the scatterer and in th e far field, and to confirm that, contrary to standard boundary integr al equation formulations, the present procedure is valid for critical frequencies.