ISSN:
1572-9613
Keywords:
Anisotropic Brownian motion
;
convective diffusion
;
stressphoresis
;
kinetic theory
;
stochastic processes
;
nonequilibrium transport phenomena
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract An analysis is made of the effects on the diffusion of Brownian particles whose Knudsen number is large compared to unity, of nonuniformities in the host gas. As examples, in one type of nonuniformity of the host gas, the Chapman-Enskog velocity distribution function for the gas molecules is used; in the other, the host gas is a free-molecule Couette flow. In both cases, a new force on the Brownian particles appears. Two techniques are used (extending Kramers' method and utilizing the Chapman-Enskog method) to transform the new Fokker-Planck equation into generalized Smoluchowski and convective diffusion equations. In these equations, the diffusion coefficient appears as a second-order tensor. Thus, it is demonstrated that Brownian diffusion in a nonuniform gas is anisotropic.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01011385
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