We consider a model for the solidification of an ideal ternary alloy in a mushy layer that incorporates the effects thermal and solutal diffusion, convection and solidification. Our results reveal that although the temperature and solute fields are constrained to the liquidus surface of the phase diagram, the system still admits double-diffusive type modes of instability. Additionally, modes of instability exist even in situations in which the thermal and solute fields are each individually stable from a static point of view. We highlight these instabilities in a model that admits an analytical solution and then examine the instabilities in a more general setting in which the base state solution and its linear stability are computed numerically.
Citation: Journal of Fluid Mechanics
Pub Type: Journals
solidification, convection, ternary alloy, mushy zone, buoyancy