AN AXISYMMETRIC INVERSE BEM FORMULATION FOR ACOUSTIC WAVES RADIATION AND SCATTERING IN A HALF SPACE

摘要

An inverse problem solution is presented using Boundary Element Method (BEM) forrnradiation and scattering of acoustic waves in a half space. The inverse formulation isrnposed by prescribing the acoustic pressure in the filed points and the impedance of thernacoustic source is to be determined. By employing the axisymmetric property of thernbody, a simplified formulation of the BEM is obtained which is implemented in therninverse method. The inverse formulation takes adva ntage of the axisymmetric directrnBEM formulation wherein discretization is only needed for the generator of the body.rnCombined Helmholtz Integral Equation Formulation (CHIEF) method is used tornovercome the ill-conditioned nature of the surface matrix equa tion at certainrncharacteristic frequencies. Singular Value Decomposition (SVD) was employed torndetermine the number and location of the CHIEF points, and a least-square sensernsolution was sought. Test cases are presented involving spherical and cylindricalrnshape bodies mounted on an infinite plane.