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Show Modeling Pollution in Cities Department of Mechanical Engineering Detailed experiments of gas dispersion through a uniform array of cylindrical barrels were conducted on the salt flats of Utah's Western Desert, Dugway Proving Grounds. 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 as shown in the grid on the poster. Propylene tracer gas was released through a 25.4 mm diameter pipe, 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. Instantaneous concentration measurements were simultaneously acquired within the array from 40 photoionization detectors arranged in three, 50 degree arcs as shown in the photographs of the experiments. Turbulence data in the roughness sub layer and near the source were also measured using 3-6, three dimensional sonic anemometers, also shown in the photographs. 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 models used to predict dispersion in urban environments. Heidi Miner Adam Rasmussen Professor Joseph Klewicki |