Electronic Resource
Springer
Journal of statistical physics
53 (1988), S. 125-136
ISSN:
1572-9613
Keywords:
Brownian motion
;
elongational flow
;
fluctuation-dissipation theorem
;
fluctuations around stationary states
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Brownian motion of a spherical particle in stationary elongational flow is studied. We derive the Langevin equation together with the fluctuation-dissipation theorem for the particle from nonequilibrium fluctuating hydrodynamics to linear order in the elongation-rate-dependent inverse penetration depths. We then analyze how the velocity autocorrelation function as well as the mean square displacement are modified by the elongational flow. We find that for times small compared to the inverse elongation rate the behavior is similar to that found in the absence of the elongational flow. Upon approaching times comparable to the inverse elongation rate the behavior changes and one passes into a time domain where it becomes fundamentally different. In particular, we discuss the modification of thet −3/2 long-time tail of the velocity autocorrelation function and comment on the resulting contribution to the mean square displacement. The possibility of defining a diffusion coefficient in both time domains is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01011549
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