The diffusion of individual molecules within a gasThe Direct Simulation Monte Carlo method is used to study the positional history of the individual molecules in a gas that is homogeneous at the macroscopic level and is in Maxwellian equilibrium at the microscopic level. The behavior at small times is characterized by 'persistence of velocity' effects, and a 'random walk' type of dispersal occurs over a longer timescale. It is shown that the rate of dispersal can be directly related to the self-diffusion coefficient. In addition, the diffusion coefficients are obtained directly from one-dimensional calculations, and the local Knudsen number at which the Chapman-Enskog theory breaks down is determined. Results are presented for both simple gases and gas mixtures.
Document ID
19880029621
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Bird, G. A. (Sydney, University Australia)
Date Acquired
August 13, 2013
Publication Date
January 1, 1986
Subject Category
Thermodynamics And Statistical Physics
Meeting Information
Meeting: International Symposium on Rarefied Gas Dynamics