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Non-equilibrium fluctuations induced by the Soret effect in a ternary mixture
José M Ortiz de Zárate1, Cédric Giraudet, Henri Bataller
1Departamento de Física Aplicada I, Universidad Complutense, Plaza de las Ciencias, 1, 28040, Madrid, Spain, jmortizz@fis.ucm.es.
The European Physical Journal. E, Soft Matter
|August 28, 2014
Summary
This study introduces a theory for concentration fluctuations in ternary mixtures under temperature gradients, revealing a non-equilibrium enhancement proportional to the gradient squared and inversely to the wave number to the fourth power.
Area of Science:
- Thermodynamics
- Fluid Dynamics
- Physical Chemistry
Background:
- Concentration fluctuations are crucial in multicomponent mixtures.
- Thermal diffusion (Soret effect) induces composition gradients under temperature gradients.
- Understanding these fluctuations is key to predicting mixture behavior.
Purpose of the Study:
- To develop a theory for concentration fluctuations in ternary mixtures subjected to a stationary temperature gradient.
- To investigate the role of cross-diffusion effects in these fluctuations.
- To analyze the impact of non-equilibrium conditions on fluctuation enhancement.
Main Methods:
- Application of fluctuating hydrodynamics theory.
- Consideration of a generic diffusion matrix, including cross-diffusion.
- Neglect of gravity and confinement effects for asymptotic analysis.
Main Results:
- A significant non-equilibrium enhancement of concentration fluctuations was found.
- This enhancement is proportional to the square of the temperature gradient.
- The fluctuations are inversely proportional to the fourth power of the wave number (q^-4).
Conclusions:
- The presented theory provides insights into concentration fluctuations in ternary mixtures under thermal gradients.
- The results are asymptotically valid for large wave numbers (q).
- Gravity and confinement effects become important for smaller wave numbers and require further investigation.
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