Title: Unstable density stratification in binary mixture

Authors: V. Shevtsova, D. Melnikov, J.C. Legros

Addresses: MRC, Department of Chemical Physics, E.P., CP-165/62, University of Brussels (ULB), 50, av. F.D. Roosevelt, B-1050 Brussels, Belgium. ' MRC, Department of Chemical Physics, E.P., CP-165/62, University of Brussels (ULB), 50, av. F.D. Roosevelt, B-1050 Brussels, Belgium. ' MRC, Department of Chemical Physics, E.P., CP-165/62, University of Brussels (ULB), 50, av. F.D. Roosevelt, B-1050 Brussels, Belgium

Abstract: Three-dimensional numerical modelling of Soret driven convection in a cubic cell filled with a binary mixture of water (90%) and isopropanol (10%) is performed. The system is heated from above while the Soret coefficient is negative. The concentration and temperature fields are strongly coupled by Soret effect that causes concentration gradients in response to the applied temperature difference. Due to negative Soret effect the heavier liquid is accumulated on the top of the lighter one. At some moment this unstable stratification leads to appearing of motion. The transient behaviour of the velocity, temperature and concentration fields is discussed.

Keywords: Soret effect; buoyancy force; convection; oscillation; instability; unstable density stratification; binary mixtures; 3D modelling; heat transfer; mass transfer.

DOI: 10.1504/PCFD.2006.010776

Progress in Computational Fluid Dynamics, An International Journal, 2006 Vol.6 No.6, pp.348 - 356

Published online: 30 Aug 2006 *

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