AN INTERFACE TRACKING METHOD APPLIED TO MORPHOLOGICAL EVOLUTION DURING PHASE-CHANGE

The focus of this work is the numerical simulation of interface motion during solidification of pure materials. First, we assess the applica bility of the oft-used quasi-stationary approximation for interface mo tion. Such an approximation results in poor accuracy for non-trivial S tefan numbers. Next, a generic interface tracking procedure is designe d, which overcomes restrictions of single-valuedness of the interface imposed by commonly used mapping methods. This method incorporates wit h ease interface phenomena involving curvature, which assume importanc e at the smaller scales of a deformed interface. The method is then ap plied to study the development of a morphologically unstable phase int erface. The issue of appropriate scaling has been addressed. The Gibbs -Thomson effect for curved interfaces has been included. The evolution of the interface, with the competing mechanisms of undercooling and s urface tension is found to culminate in tip-splitting, cusp formation and persistent cellular development.