The interface morphology of a spherical crystal in the undercooled melt affected by a far-field uniform flow

The effect of the convective flow caused by the far-field uniform flow on the interface morphology of a spherical crystal is studied by using the matched asymptotic expansion method. For the case that the far-field uniform flow is far less than the characteristic velocity of the interface, we obtain the uniformly valid asymptotic solution of the spherical crystal in the entire melt region. The analytical results show that the far-field uniform flow has significant effect on the interface morphology of the spherical crystal. The convection flow makes the interface of the growing spherical crystal enhance growth velocity in the upstream direction of the far-field uniform flow, inhibit growth in the downstream direction and decrease growth velocity on the two sides of the spherical crystal. The drag effect of the far-field uniform flow makes the interface morphology of the spherical crystal evolve into a pearlike oval shape. Our analytical result is consistent with the experimental and simulation results. (C) 2011 American Institute of Physics. [doi:10.1063/1.3579424]