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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Non-equilibrium concentration fluctuations in binary liquids with realistic boundary conditions
J M Ortiz de Zárate1, T R Kirkpatrick2,3, J V Sengers2
1Departamento de Fısica Aplicada I, Facultad de Fısica, Universidad Complutense, 28040, Madrid, Spain. jmortizz@fis.ucm.es.
Abstract:
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.
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