CONVECTIVE PATTERNS IN ROTATING BINARY-MIXTURES

A few-mode Lorenz-like model for convection in a rotating binary mixture confined between stress-free, impermeable boundaries is presented. It describes for positive separation ratios standing patterns of convective rolls in mutually perpendicular directions and the superposition of these rolls with the same wave number. The model is used to investigate the effect of slow rotation on convective patterns. In ideal systems squares are unstable, and the dynamical behavior immediately in the Rayleigh regime is chaotic. Side-wall forcing is incorporated by introducing a small inhomogeneity into the model. In the presence of side walls the chaotic behavior disappears, squares are stabilized close to onset, and rolls are stable in the Rayleigh regime with oscillations occurring in between. For Taylor numbers above a critical value, oscillations disappear and stable stationary patterns are possible over the whole range of Rayleigh numbers. © 1990 The American Physical Society.