AN EXACT ABSORBING BOUNDARY-CONDITION AND ITS APPLICATION TO 3-DIMENSIONAL SCATTERING FROM THIN DISPERSIVE STRUCTURES

It is emphasized that the three-dimensional time-domain wave-splitting formalism provides an ''absorbing'' (or ''radiation'') boundary condi tion which is exact. When the splitting operator is known in an explic it form which can be implemented numerically, this can be used to adva ntage in scattering computation. In the present paper this fact is exp loited in a time-domain computation of three-dimensional scattering fr om a slab characterized by an inhomogeneous dispersion (i.e., memory f unction; in general this function depends, besides on the time variabl e, on all three Cartesian space coordinates). Numerical results based on the exact absorbing boundary condition are given, and compared with results using a local approximation of the exact condition. (C) 1996 Acoustical Society of America.