Morphological instability of the sea ice – ocean interface in the presence of brine channels in a mushy layer

Abstract

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.

The formation of brine channels during the solidification process has a significant impact on the structure of the two-phase zone (mushy layer). They are responsible for the formation of another crystallization scenario and the generation of corrugations of the sea ice–ocean interface. The physical mechanism relies on brine flows developing in the sea ice due to Bernoulli suction by flow of ocean past the liquid–mushy layer interface. This mechanism should be particularly very important during sea ice freezing in wind-maintained coastal polynyas and in leads changing thermal fluxes and the heat and mass balance of the Arctic sea ice cover. Generally speaking, a true criterion of the formation of such a regime is connected with the morphological stability analysis of the mushy layer crystallization with respect to small perturbations of its morphology. In the present paper, we develop the morphological stability analysis of the directional crystallization with brine channels in a two-phase region and give a new stability criterion taking into account perturbations in the impurity concentration (salinity) and solid fraction distributions for the case of nonturbulent and turbulent boundary conditions at the mush–ocean interface.