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Simulated Flow and Dispersion of the Jack Rabbit II Field Experiment within EPA’s Fluid Modeling Facility Wind Tunnel
Citation:
Pirhalla, M., D. Heist, S. Perry, L. Brouwer, S. Hanna, S. Arya, AND V. Aneja. Simulated Flow and Dispersion of the Jack Rabbit II Field Experiment within EPA’s Fluid Modeling Facility Wind Tunnel. To be Presented at American Meteorological Society, Boston, Massachusetts, January 12 - 16, 2020.
Impact/Purpose:
This presentation describes a wind tunnel study performed within EPA's Fluid Modeling Facility based on the 2015 and 2016 Jack Rabbit II (JRII) field study. The JRII study was conducted at Dugway Proving Ground (DPG), UT, where 10-20-ton releases of chlorine gas were dispersed within an array of 83 CONEX shipping containers of various sizes. The individual CONEXs, as well as a 2x3 “tall building” stack, were meant to mimic buildings within an urban area in an effort to provide information to improve models and emergency response techniques. During a supplementary Special Sonic Study at DPG, flow and turbulence around the obstacles were measured from a network of 30 sonic anemometers dispersed around the CONEX array and can be compared to data gathered within the meteorological wind tunnel. The results are directly applicable to emergency planners, responders, or researchers who may use a fast-response model for urban dispersion studies and predictions.
Description:
In this project, a 1:50 scaled model of the JRII test area was constructed and tested within EPA’s Fluid Modeling Facility (FMF) Meteorological Wind Tunnel (MWT) to thoroughly examine the complex flow and dispersion patterns within this mock urban environment. The goal of this presentation is to explain the results of the simulated JRII wind tunnel project, including wind flow and dispersion patterns. A neutrally buoyant tracer was released into the scaled JRII array and the subsequent downwind dispersion was analyzed, including plume widths, thicknesses, and other dispersion criteria. Some emphasis is placed on comparing the wind tunnel data against observations at the test site, particularly in wakes and recirculation zones of the CONEX buildings. The ultimate goal is to use the wind tunnel and field datasets to inform improved urban parameterizations in Gaussian dispersion models. These models have been shown to be important tools for efficient and precise emergency preparation and response applications.