title: Long-wavelength nonequilibrium concentration fluctuations induced by the Soret effect.
abstract: In this paper we evaluate the enhancement of nonequilibrium concentration fluctuations induced by the Soret effect when a binary fluid layer is subjected to a stationary temperature gradient. Starting from the fluctuating Boussinesq equations for a binary fluid in the large-Lewis-number approximation, we show how one can obtain an exact expression for the nonequilibrium structure factor in the long-wavelength limit for a fluid layer with realistic impermeable and no-slip boundary conditions. A numerical calculation of the wave-number dependence of the nonequilibrium enhancement and of the corresponding decay rate of the concentration fluctuations is also presented. Some physical consequences of our results are briefly discussed.
authors.affiliation: Departamento de Física Aplicada I, Facultad de Física, Universidad Complutense, E28040 Madrid, Spain. jmortizz@fis.ucm.es
authors.forename: José María
authors.initials: JM
authors.lastname: Ortiz de Zárate
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Fornés
authors.forename: Jan V
authors.initials: JV
authors.lastname: Sengers