Velocity Statistics of Round, Fully-Developed, Buoyant Turbulent Plumes.
Velocity Statistics of Round, Fully-Developed, Buoyant
Dai, Z.; Tseng, L. K.; Faeth, G. M.
American Society of Mechanical Engineers. Fire,
Combustion, and Hazardous Waste Processing. HTD-Vol.
296. November 6-11, 1994, Chicago, IL, American Society
of Mechanical Engineers, NY, Acharya, S.; Annamalai, K.;
Presser, C.; Skocypec, R. D., Editor(s)(s), 47-54 pp,
Sponsor:National Institute of Standards and Technology,
combustion; hazardous materials; waste disposal; fire
plumes; velocity; scaling
An experimental study of the structure of round buoyant
turbulent plumes was carried out, limited to conditions
within the fully developed (self-preserving) portion of
the flow. Plume conditions were simulated using dense
gas sources (carbon dioxide and sulfur hexafluoride) in
a still air environment. Velocity statistics were
measured using laser velocimetry in order to supplement
earlier measurements of mixture fraction statistics
using laser-induced iodine fluorescence. Similar to the
earlier observations of mixture fraction statistics,
self-preserving behavior was observed for velocity
statistics over the present test range (87-151 source
diameters and 12-43 Morton length scales from the
source), which was farther from the source than most
earlier measurements. Additionally, the new
measurements indicated that self-preserving plumes are
narrower, with larger mean streamwise velocities near
the axis (when appropriately scaled) and with smaller
entrainment rates, than previously thought. Velocity
statistics reported include mean and fluctuating
velocities, temporal power spectra, temporal and spatial
integral scales and Reynolds stresses.