Extended Abstract (268K)P1.2
Near surface atmospheric plume dispersion through a compact cylinder array
Heidi E. Miner, University of Utah, Salt Lake City, UT; and M. M. Metzger, J. C. Klewicki, A. Rasmussen, and A. Venkatram
Detailed experiments of near-field plume dispersion through a uniform array of cylindrical barrels were conducted on the salt flats of Utah's Western Desert. A 5 x 9 rectangular array of 45 barrels, height H=0.91 m and diameter d=0.57 m, was constructed with a barrel spacing of 1.8 m, center to center. Propylene tracer gas was released through a 25.4 mm diameter pipe, both upstream and within the barrel array. The dissemination rate was fixed at 15 slm using a mass flow controller. The tracer source was located at both ground level and 1H. At each of the two source heights, four different barrel configurations were arranged near the source. In the first and second configurations, the source was located directly upwind of a single barrel and two barrels placed side by side, respectively. In the third configuration the source was surrounded by four barrels. In the final configuration the source was located directly upwind of a three barrel pyramid. Instantaneous concentration measurements were simultaneously acquired within the array from 40 photoionization detectors arranged in three, 50 degree arcs. Turbulence data in the roughness sub layer and near the source were also measured using 3-6, three dimensional sonic anemometers. Overall, 13.5 hours of data were collected spanning 4 days. Atmospheric stability during the experiments ranged between -0.8 < z < 0.4, where z denotes the Monin-Obukhov stability parameter as calculated from a sonic anemometer located at a height of 3.2 m. Results include statistical profiles, distributions, and intermittency factors of the concentration within the array as a function of source configuration and atmospheric stability. Results from the study will benefit both the physical understanding of near-field plume behavior in the presence of surface mounted obstacles as well as the development of Lagrangian stochastic models used to predict dispersion in urban environments.
Poster Session 1, FLOW AND DISPERSION STUDIES
Wednesday, 22 May 2002, 3:00 PM-5:00 PM
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