A UNIFIED VARIATIONAL APPROACH TO DOMAIN-BASED COMPUTATION OF EXTERIOR PROBLEMS OF TIME-HARMONIC ACOUSTICS

A general framework for domain-based computation in unbounded regions, with particular reference to time-harmonic acoustics, is based on a f unctional for partitioned problems, weakly enforcing continuity of inn er and outer fields. Two prominent features of this formulation simpli fy the task of discretization: the lack of integration over the unboun ded domain, and accommodation of incompatible approximations. The spec ific formulation depends on the representation of the outer held. Exam ples of formulations employing DtN boundary conditions are reproduced. A novel approach to infinite element formulations is presented, leadi ng to various approximations for two-dimensional configurations with c ircular interfaces. Numerical results demonstrate the good performance of these schemes. (C) 1998 Elsevier Science B.V. and IMACS. All right s reserved.