Symmetry Breaking Flow Transitions And Oscillatory Flows In A 3d Solidification Model

Abstract

This study focus on the 3D character of flow and the loss of symmetry that produces some unsteadiness
and perturbs the shape and the dopant distribution in configurations interesting directional solidification. Only
hydrodynamic in the melt is analyzed. The critical stability limited for the onset of the natural convection under 2D
assumption is extended to a preliminary 3D investigation. It is found that the initial steady symmetric flow becomes
asymmetric for lower Ra number in comparison to the 2D approach. The loss of symmetry occurs first in the
transversal plan. For relative low Ra it is observed that the heat transfer increases on the bottom active wall and
decreases on the vertical acting walls without significant intensification in the global transfer. The classical spiral
characterizing the 3D effect of the surface limiting the domain is also observed.