INFLUENCE OF THE DUFOUR EFFECT ON CONVECTION IN BINARY GAS-MIXTURES

Linear and nonlinear properties of convection in binary fluid layers h eated from below are investigated, in particular for gas parameters. A Galerkin approximation for realistic boundary conditions that describ es stationary and oscillatory convection in the form of straight paral lel rolls is used to determine the influence of the Dufour effect on t he bifurcation behavior of convective how intensity, vertical heat cur rent, and concentration mixing. The Dufour-induced changes in the bifu rcation topology and the existence regimes of stationary and traveling -wave convection are elucidated. To check the validity of the Galerkin results we compare them with finite-difference numerical simulations of the full hydrodynamical field equations. Furthermore, we report on the scaling behavior of linear properties of the stationary instabilit y.