Shear dispersion and turbulence decorrelation by differential rotation

Garcia, O.E. and Bian, N.H. (2005) Shear dispersion and turbulence decorrelation by differential rotation. Physics of Plasmas, 12(1), 014503. (doi: 10.1063/1.1828082)

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Abstract

The shear enhanced dispersion of a passive scalar field subject to differential rotation is investigated analytically and interpretations are given in terms of turbulence shear decorrelation. Using the method of advected coordinates, the enhanced dispersion caused by steady and oscillatory flows with uniform shear is derived and the well-known turbulence shear decorrelationtheory is recovered. The additional role of kinetic energy transfer due to differential advection of vorticity is also pointed out. Finally, the shear enhanced dispersion due to flows with periodic variations in space as well as time is given. It is found that radially alternating flows may significantly reduce the turbulencedecorrelation time provided the root mean square flow shear is larger than the flow oscillation frequency. In the opposite limit of fast flow oscillations there is no turbulencedecorrelation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Bian, Dr Nicolas Horace
Authors: Garcia, O.E., and Bian, N.H.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physics of Plasmas
Publisher:American Institute of Physics
ISSN:1070-664X
ISSN (Online):1089-7674

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