Influence of separation ratio on Rayleigh-Bénard convection solutions in a binary fluid mixture

Abstract

The Rayleigh-Bénard convection in a binary fluid mixture is one of typical models for studying the nonlinear dynamics of nonequilibrium convection. In this paper, using the numerical simulations of the two-dimensional full equations of hydrodynamics, we study the bifurcation and evolution of patterns in the traveling wave convection in binary fluid mixtures with strong Soret effect (separation ratio Ψ=-0.60) in a rectangular cell. The system exhibits 5 types of traveling wave convection solutions with the increasing of reduced Rayleigh number r along the upper branch of the bifurcation curve. They are localized traveling wave convection, traveling wave convection with defects, traveling wave convection, undulation traveling wave convection, and stationary overturning convection. Second, the influence of separation ratio on convection solutions is investigated. By comparing the convection solutions with strong Soret effect (Ψ=-0.60) with those of weakly Soret effect (Ψ=-0.11), we find that those with strong Soret effect are richer. Because of the complexity in convection with strong Soret effect, the convection solutions at Ψ=-0.60 are different from those at Ψ=-0.20, -0.4.