Numerical analysis of binary fluid convection with thermal and solutal lateral gradients

This paper analyzes the influence of laterally enforced solutal gradients on the steady and bifurcated periodic dynamics in binary fluids contained in horizontally heated slots, taking into account the Soret and Dufour effects. Numerical Newton-Krylov continuation techniques to follow the primary and secondary branches of steady solutions and periodic orbits are applied. The stability of all these branches is also analyzed. A great variety of stable steady and periodic states is found, depending on the ratio of the thermal and solutal gradients. The proximity to parameters that balance the buoyancy forces delays the onset of center-symmetric oscillations to very large values of the thermal Rayleigh number, while large solutal gradients tend to restabilize the steady flows after the onset of center-symmetric oscillations, and to give rise to spatiotemporal symmetric waves of broken center symmetry at larger thermal Rayleigh number. The work done by the thermal buoyancy force is essential for the restabilization of the steady states and the change of the ulterior dynamics. It is also shown that the transition to temporal chaos depends strongly on the absence or intensity of the solutal gradients.