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Self-Preserving Buoyant Turbulent Plumes.


pdf icon Self-Preserving Buoyant Turbulent Plumes. (808 K)
Faeth, G. M.

NISTIR 6030; June 1997.

U.S./Japan Government Cooperative Program on Natural Resources (UJNR). Fire Research and Safety. 13th Joint Panel Meeting. Volume 1. March 13-20, 1996, Gaithersburg, MD, Beall, K. A., Editor(s), 275-284 pp, 1997.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Available from:

National Technical Information Service
Order number: PB97-184204

Keywords:

fire safety; fire research; buoyant plumes; equations

Abstract:

An experimental study of round buoyant turbulent plumes is described, emphasizing conditions where the flow has lost source momentum and other source distrubances, and has become self preserving. Plume conditions were simulated using dense gas sources in a still and unstratified air environment. Mean and fluctuating mixture fractions and velocities were measured using laser-induced fluorescence and laser velocimetry, respectively. The present measurements extended farther from the source than most earlier work (up to 151 source diameters and 43 Morton length scales) and show that self-preserving plumes are narrower and have large mean properties near the axis than previously thoght. Although contemporary turbulence models yield reasonably good predictions of mean properties in the self-preserving region, there are difficulties with many of the approximations concerning turbulence properties; this raises questions about the potential effectiveness of these models for predicting the properties of the complex buoyant turbulent flows that are encountered in practical fire environments.