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Updated: Aug 14, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Correlated fluctuating hydrodynamics. I. Persistent transport from spatial correlations
Sijie Huang1,2,3, Ayush Saurabh1,2,3, Steve Pressé1,2,3,4
1Department of Physics, Arizona State University, Tempe, Arizona 85287, USA.
The Journal of Chemical Physics
|August 12, 2026
Summary
Spatially correlated thermal fluctuations in fluids significantly alter mesoscopic transport. These correlations can enhance or suppress particle diffusion, delaying the transition to normal diffusion compared to uncorrelated fluctuations.
Area of Science:
- Physics
- Fluid Dynamics
- Statistical Mechanics
Background:
- Fluctuations from molecular motion influence transport in fluids at mesoscopic scales.
- Thermal fluctuations are often assumed to be spatially uncorrelated, but fluid microstructure can induce correlations.
Purpose of the Study:
- To investigate how spatially correlated thermal fluctuations impact mesoscopic transport in fluids.
- To develop a fluctuating-hydrodynamic framework incorporating correlated thermal noise.
Main Methods:
- Developed a fluctuating-hydrodynamic framework with spatially correlated thermal noise.
- Ensured thermal equilibrium via the fluctuation-dissipation relation, linking noise injection to viscous dissipation.
- Performed numerical simulations of particle diffusion.
Main Results:
- Increasing correlation length significantly prolongs transport persistence, delaying crossover to normal diffusion.
- Correlated thermal fluctuations can either enhance or suppress transport persistence compared to Brownian diffusion.
- Viscous dissipation inherits spatial correlations, modifying momentum diffusion.
Conclusions:
- Intrinsic spatial correlations in equilibrium thermal fluctuations fundamentally reshape mesoscopic transport.
- The framework provides insights into the coupling of correlated fluctuations and hydrodynamics.
- Understanding these correlations is crucial for accurately modeling mesoscopic transport phenomena.
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