Further aspects of the Kelvin transformation method for dealing with open boundaries

The authors previously described a technique for allowing for open boundaries in finite element problems (1988, 1989). In the present work the ideas are extended to accommodate materials and sources in the outer region. The important point is made that for Cartesian geometries the transformed region can be of any reasonable size and it can be placed in any convenient position. It is shown that regions having uniform fields can easily be produced by placing the appropriate Dirichlet boundary at a significant distance in the outer region. The transformation of an outer region containing a semi-infinite highly permeable block is demonstrated