https://doi.org/10.1140/epje/i2015-15099-x
Regular Article
Non-equilibrium concentration fluctuations in binary liquids with realistic boundary conditions
1
Departamento de Fısica Aplicada I, Facultad de Fısica, Universidad Complutense, 28040, Madrid, Spain
2
Institute for Physical Science and Technology, University of Maryland, 20742, College Park, Maryland, USA
3
Department of Physics, University of Maryland, 20742, College Park, Maryland, USA
* e-mail: jmortizz@fis.ucm.es
Received:
6
May
2015
Revised:
18
August
2015
Accepted:
20
August
2015
Published online:
21
September
2015
Because of the spatially long-ranged nature of spontaneous fluctuations in thermal non-equilibrium systems, they are affected by boundary conditions for the fluctuating hydrodynamic variables. In this paper we consider a liquid mixture between two rigid and impervious plates with a stationary concentration gradient resulting from a temperature gradient through the Soret effect. For liquid mixtures with large Lewis and Schmidt numbers, we are able to obtain explicit analytical expressions for the intensity of the non-equilibrium concentration fluctuations as a function of the frequency ω and the wave number q of the fluctuations. In addition we elucidate the spatial dependence of the intensity of the non-equilibrium fluctuations responsible for a non-equilibrium Casimir effect.
Key words: Flowing Matter: Liquids and Complex Fluids
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2015