BOUNDARY INFINITE ELEMENTS FOR THE HELMHOLTZ-EQUATION IN EXTERIOR DOMAINS

A novel approach to the development of infinite element formulations f or exterior problems of time-harmonic acoustics is presented. This app roach is based on a functional which provides a general framework for domain-based computation of exterior problems. Special cases include n on-reflecting boundary conditions (such as the DtN method). A prominen t feature of this formulation is the lack of integration over the unbo unded domain, simplifying the task of discretization. The original for mulation is generalized to account for derivative discontinuities acro ss infinite element boundaries, typical of standard infinite element a pproximations. Continuity between finite elements and infinite element s is enforced weakly, precluding compatibility requirements. Various i nfinite element approximations for two-dimensional configurations with circular interfaces are presented Implementation requirements are rel atively simple. Numerical results demonstrate the good performance of this scheme. (C) 1998 John Wiley & Sons, Ltd.