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Flatness of tracer density profile produced by a point source in turbulence

Gleeson, James P. and Pullin, D. I. (2003) Flatness of tracer density profile produced by a point source in turbulence. Physics of Fluids, 15 (11). pp. 3546-3557. ISSN 1070-6631.

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The average concentration of tracers advected from a point source by a multivariate normal velocity field is shown to deviate from a Gaussian profile. The flatness (kurtosis) is calculated using an asymptotic series expansion valid for velocity fields with short correlation times or weak space dependence. An explicit formula for the excess flatness at first order demonstrates maximum deviation from a Gaussian profile at time t of the order of five times the velocity correlation time, with a t–1 decay to the Gaussian value at large times. Monotonically decaying forms of the velocity time correlation function are shown to yield negative values for the first order excess flatness, but positive values can result when the correlation function has an oscillatory tail.

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Additional Information:©2003 American Institute of Physics. Received 25 November 2002; accepted 18 August 2003; published online 1 October 2003. This project was partly funded by the Enterprise Ireland International Collaboration Fund, Science Foundation Ireland Investigator Award 02/IN.1/IM062, and by a research grant from the Faculty of Arts, University College Cork.
Subject Keywords:Gaussian distribution; tracers; turbulence
Issue or Number:11
Record Number:CaltechAUTHORS:GLEpof03
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4338
Deposited By: Tony Diaz
Deposited On:18 Aug 2006
Last Modified:02 Oct 2019 23:12

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