Large Scale Simulation of Dendritic Growth in Pure Undercooled Melt by Phase-field Model.

In this study we presented a double-grid method for efficient computation of complex dendritic pattern evolving in a large scale solidifying system of pure undercooled melt. The method, which is based on the large difference in phase-field diffusivity and thermal diffusivity in pure material, enables us to use a large time step. The phase field was calculated adaptively only on the grids within the interfacial region and also the thermal field was calculated only within the thermal boundary layer. The computation showed that the complex dendritic patterns with well-developed tertiary arms can be obtained even in a personal computer with a moderate memory space. The computational efficiency of this method, the competitive growth and coarsening of the secondary arms and the tertiary branching from secondary arms were discussed.