title: Effects of a temperature-dependent viscosity on thermal convection in binary mixtures.
abstract: We investigate the effect of a temperature-dependent viscosity on the onset of thermal convection in a horizontal layer of a binary fluid mixture that is heated from below. For an exponential temperature dependence of the viscosity, we find, in binary mixtures as a function of a positive separation ratio ψ and beyond a certain viscosity contrast, a discontinuous transition between two stationary convection modes having different wavelengths. In the range of negative values of the separation ratio ψ, a (continuous or discontinuous) transition from an oscillatory to a stationary onset of convection occurs beyond a certain viscosity contrast, and for large values of the viscosity ratio, the oscillatory onset of convection is suppressed.
authors.affiliation: Theoretische Physik I, Universität Bayreuth, 95440 Bayreuth, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Hilt
authors.affiliation: Theoretische Physik I, Universität Bayreuth, 95440 Bayreuth, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Glässl
authors.affiliation: Theoretische Physik I, Universität Bayreuth, 95440 Bayreuth, Germany.
authors.forename: Walter
authors.initials: W
authors.lastname: Zimmermann