Abstract
Molecular-dynamic studies of the behavior of the diffusion coefficient after a long time $s$ have shown that the velocity autocorrelation function decays as ${s}^{\ensuremath{-}1}$ for hard disks and as ${s}^{\ensuremath{-}\frac{3}{2}}$ for hard spheres, at least at intermediate fluid densities. A hydrodynamic similarity solution of the decay in velocity of an initially moving volume element in an otherwise stationary compressible viscous fluid agrees with a decay of ${(\ensuremath{\eta}s)}^{\ensuremath{-}\frac{d}{2}}$, where $\ensuremath{\eta}$ is the viscosity and $d$ is the dimensionality of the system. The slow decay, which would lead to a divergent diffusion coefficient in two dimensions, is caused by a vortex flow pattern which has been quantitatively compared for the hydrodynamic and molecular-dynamic calculations.
Keywords
PhysicsAutocorrelationDiffusionViscosityCompressibilityFunction (biology)ThermodynamicsMathematics
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Publication Info
- Year
- 1970
- Type
- article
- Volume
- 1
- Issue
- 1
- Pages
- 18-21
- Citations
- 1344
- Access
- Closed
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Cite This
B. J. Alder,
T. E. Wainwright
(1970).
Decay of the Velocity Autocorrelation Function.
Physical review. A, General physics
, 1
(1)
, 18-21.
https://doi.org/10.1103/physreva.1.18
Identifiers
- DOI
- 10.1103/physreva.1.18