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Diffusive mass transfer by nonequilibrium fluctuations: Fick's law revisited
1Dipartimento di Fisica and Istituto Nazionale per la Fisica della Materia, Università degli Studi di Cagliari Strada Provinciale Monserrato-Sestu km 0,7, 09042 Monserrato, CA, Italy.
Summary
Giant fluctuations in liquid systems do not alter mass transfer, aligning with Fick's law. Gravitational effects on diffusion coefficients are quantified by stabilizing long wavelength fluctuations.
Area of Science:
- Physics
- Physical Chemistry
- Fluid Dynamics
Background:
- Giant fluctuations are observed in liquid systems during diffusion.
- Nonequilibrium fluctuations significantly impact mass transfer dynamics.
Purpose of the Study:
- To calculate net mass transfer caused by nonequilibrium fluctuations in liquid systems.
- To investigate the influence of gravitational effects on diffusion coefficients.
Main Methods:
- Linearized fluctuating hydrodynamics was employed.
- Hydrodynamic equations were renormalized to analyze gravitational modifications.
Main Results:
- Net mass transfer due to fluctuations was found to be consistent with Fick's law.
- Gravitational stabilization of long wavelength fluctuations modifies the diffusion coefficient.
Conclusions:
- Nonequilibrium fluctuations do not change the fundamental mass transfer described by Fick's law.
- The study quantifies how gravity influences diffusion through fluctuation stabilization.