Determination of Far-Field Pattern of Rigid Scatterers Using Independent Finite Element Method and Eigenfunction Expansion, Part 2: Nonaxisymmetric Scattering

Abstract

The near- and far-field steady state scattered potentials around a rigid arbitrary obstacle subjected to plane incident wave are computed by FE and eigenfunction expansion approach. The near-field is bounded by a truncation surface which is spherical. The nonaxisymmetric damper equation developed by Bayliss et al. (SIAM J. Appl. Math. Vol. 42, pp. 430–451, 1982) is employed on this surface. The computed FE near-field potential on the truncation boundary is employed as a Dirichlet boundary condition to obtain the expansion coefficients which eventually help in obtaining the complete solution in the entire outer domain including the far-field. The numerical technique is applied to problems of rigid scattering of beam-on- and oblique-incident waves by rigid prolate spheroid and hemispherically capped cylinder and contour plots of far-field scattered potential are presented.