in the melt [Physica D 135 (2000) 175]. This model represents the two phases as viscous
liquids, where the putative solid phase has a viscosity much larger than the liquid phase.
The object of this paper is to examine in detail a simplified version of the governing
equations for this phase-field model in the sharp-interface limit to derive the interfacial
conditions of the associated free-boundary problem. The importance of this analysis is that it …