A NEWTON-RAPHSON PSEUDO-SOLID DOMAIN MAPPING TECHNIQUE FOR FREE AND MOVING BOUNDARY-PROBLEMS - A FINITE-ELEMENT IMPLEMENTATION

An implicit, pseudo-solid domain mapping technique is described that f acilitates finite element analysis of free and moving boundary problem s. The technique is based on an implicit, full-Newton strategy,free of restrictions on mesh structure; this leads to many advantages over ex isting domain mapping techniques. The fully coupled approach using New ton's method is particularly effective for problems with strong coupli ng between the internal bulk physics and the governing physics at unkn own free boundary locations. It is also useful when the distinguishing conditions which constrain the free boundary shape provide only an im plicit dependence on the boundary location. Unstructured meshes allow for efficient resolution of internal and boundary layers and other reg ions of strong local variations in the solution and they also reduce t he amount of user interaction required to define a problem since the m eshes may be generated automatically. The technique is readily applied to steady or transient problems in complex geometries of two and thre e dimensions. Examples are shown that include free and moving boundary problems from solidification and capillary hydrodynamics. (C) 1996 Ac ademic Press, Inc.