INFLUENCE OF THROUGH-FLOW ON LINEAR PATTERN-FORMATION PROPERTIES IN BINARY MIXTURE CONVECTION

We investigate how a horizontal plane Poiseuille shear flow changes li near convection properties in binary fluid layers heated from below. T he full linear field equations are solved with a shooting method for r ealistic top and bottom boundary conditions. Relevant characteristic g rowth exponents and the spatial structure of their associated eigenfun ctions are evaluated for different perturbations of the conductive sta te. Through-flow induced changes of the bifurcation thresholds (stabil ity boundaries) for different types of convective solutions are determ ined in the control parameter space spanned by Rayleigh number, Soret coupling (positive as well as negative), and through-flow Reynolds num ber. We elucidate the through-flow induced lifting of the Hopf symmetr y degeneracy of left and right traveling waves in mixtures with negati ve Soret coupling. Finally we determine with a saddle point analysis o f the complex dispersion relation of the field equations over the comp lex wave number plane the borders between absolute and convective inst abilities for different types of perturbations in comparison with the appropriate Ginzburg-Landau amplitude equation approximation.