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ENVIRONMENTAL CFD SIMULATION AND VISUALIZATION: EXAMPLES IN SUPPORT OF THE RECONSTRUCTION OF THE SMOKE/DUST PLUME FROM THE WORLD TRADE CENTER SITE FOLLOWING THE EVENTS OF SEPTEMBER 11, 2001
Citation:
Huber, A H., M. Freeman, AND K. H. Kuehlert. ENVIRONMENTAL CFD SIMULATION AND VISUALIZATION: EXAMPLES IN SUPPORT OF THE RECONSTRUCTION OF THE SMOKE/DUST PLUME FROM THE WORLD TRADE CENTER SITE FOLLOWING THE EVENTS OF SEPTEMBER 11, 2001. Presented at Science Forum 2003, Washington, DC, May 5-7, 2003.
Impact/Purpose:
The goal of this research to develop models and computational tools to improve understanding of the functional relationships underlying human exposure to air toxics, and to reduce uncertainty in estimates of exposure to individuals and populations of concern. This goal will be met by addressing a number of key objectives in this task and include:
Model Research and Development: develop a multiroute/pathway/media human exposure and dose model for air toxics.
Model Application: apply model to an urban area (Houston, TX) to estimate human population exposure and dose.
Model Performance Evaluation: compare and evaluate exposure and dose estimates with independent model estimates or personal exposure measurements
Description:
The Poster will present the process of Computational Fluid Dynamics (CFD) simulations through examples supporting the reconstruction of the smoke/dust plumes following the collapse of the WTC towers on September 11, 2001.
Understanding the pathway of toxic air pollutants from source to human exposure in urban areas is of critical interest to the US Environmental Protection Agency, and finds immediate application in the Agency's role in Homeland Security. The collapse of the New York World Trade Center (WTC) Towers demonstrated clearly to EPA/ORD some of the shortcomings in conducting rapid exposure and risk analyses in urban areas, with their complex topology and large populations. Yet, rapid assessments of risk are vital to first responders, local officials, federal officials, and the public. The scientific shortcomings are especially serious for incidents that occur in an urban center where the understanding of airflow around large buildings is poor.
Computational Fluid Dynamic (CFD) simulations have long been used in the aerospace and automotive industries to evaluate air flow around planes and cars. CFD simulations are relatively new to applications in environmental science because of the temporal and spatial scales, and the complex chaotic nature of the physical processes in environmental problems. CFD techniques can be employed to describe the flow of pollutants (be they a plume from an event like the WTC collapse and fires, or be they the dispersion of some pollutant or agent) in the complex terrain that our urban areas represent. CFD simulations have the ability of closely matching the true geometry of the buildings and the "real world" physical processes. CFD simulations can be used directly or can be used as a foundation for developing reliable simplified models for rapid risk assessment.
ORD has adapted its research - using high performance computing technology and applications of Computational Fluid Dynamics (CFD) and Scientific Visualization to provide better descriptions of the complex air flow in urban environments and the distribution of pollutants carried by this air flow. The effort includes using actual field measurement data from New York, together with measurements from a scale-model of the WTC site in EPA's Fluid Modeling Facility, to provide evaluations of the CFD simulations of the WTC plume. The developments are a collaboration among EPA Office of Research and Development's National Exposure Research Laboratory and National Center for Exposure Assessment, EPA Office of Environmental Information's Scientific Visualization Center, and Fluent Inc. The applications are a collaboration with EPA Region 2 and the Environmental and Occupational Sciences Institute. The objective of this effort is to provide a sound scientific basis for rapid models of exposure and risk in urban areas for use by responders and emergency management personnel.