Stability analysis of a planar liquid/solid interface of directional solidification in pure melt under perturbation of a far-field flow

The stability of a planar liquid/solid interface of solidification in pure melt under perturbation of a small far-field flow was studied by using asymptotic analysis. A dispersion relation between the wave number and perturbation amplification rate was derived, and the morphological stability of planar liquid-solid interface of solidification was determined. The results reveal the mechanism of the transition from planar interface to cellular interface in directional solidification.