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Updated: May 26, 2026

Evolution of Staircase Structures in Diffusive Convection
Published on: September 5, 2018
Three-dimensional convection of binary mixtures in porous media
1Institut für Theoretische Physik, Universität des Saarlandes, Saarbrücken, Germany. rudolf@lusi.uni-sb.de
Abstract:
We investigate convection patterns of binary mixtures with a positive separation ratio in porous media. As setup, we choose the Rayleigh-Bénard system of a fluid layer heated from below. Results are obtained by a multimode Galerkin method. Using this method, we compute square and crossroll patterns, and we analyze their structural, bifurcation, and stability properties. Evidence is provided that, for a strong enough Soret effect, both structures exist as stable forms of convection. Some of their properties are found to be similar to square and crossroll convection in the system without porous medium. However, there are also qualitative differences. For example, squares can be destabilized by oscillatory perturbations with square symmetry in porous media, and their velocity isolines are deformed in the so-called Soret regime.
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