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ALOFT-PC: A Smoke Plume Trajectory Model for Personal Computers.


pdf icon ALOFT-PC: A Smoke Plume Trajectory Model for Personal Computers. (456 K)
Walton, W. D.; McGrattan, K. B.; Mullin, J. V.

NIST SP 995; Volume 2; March 2003.

Environment Canada. Arctic and Marine Oilspill Program (AMOP) Technical Seminar, 19th. Volume 2. Proceedings. June 12-14, 1996, Alberta, Canada, Environment Canada, Ottawa, Ontario, 987-997 pp, 1996.

Keywords:

oil spills; in situ burning; computer models; heat release rate; crude oil; plumes; pool fires; wind velocity; temperature profiles

Abstract:

As the understanding of the capabilities and limitations of in situ burning of oil spills increases, in situ burning continues to gain acceptance as an oil spill mitigation tool. One widely imposed criteria for the use of in situ burning is limiting the exposure of downwind populations to smoke particulate. Since the downwind distribution of smoke particulate is a complex function of the fire parameters, meteorological conditions, and topographic features, a computer based model is required to predict the smoke plume trajectory. Measurements and observations at experimental burns have shown that the downwind distribution of smoke is not Gaussian and simple smoke plume models do not capture the observed plume features. To resolve these problems, NIST has developed a smoke plume trajectory model that solves the fundamental Navier-Stokes equations using an eddy viscosity over a uniform grid which spans the smoke plume and its surroundings. This large eddy simulation smoke plume model has been refined over a period of years using a computer workstation and the results have compared favorably with the limited data available from experimental burns. ALOFT-PC (A Large Open Fire plume Trajectory model) is the public domain version of the model for windows based personal computers. The model inputs include wind speed and variability, atmospheric temperature profile, and fire parameters and the output is the average concentration of smoke in each of the computational cells from ground level to the top of the plume. ALOFT-PC is designed to aid in the in situ burn planning process. For this purpose a "foot print" of the ground level smoke concentration is the most commonly used model output.