Grantee Research Project Results

Final Report: Large Eddy Simulation of Dispersion in Urban Areas

EPA Grant Number: R828771C004
Subproject: this is subproject number 004 , established and managed by the Center Director under grant R828771
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for the Study of Childhood Asthma in the Urban Environment
Center Director: Hansel, Nadia
Title: Large Eddy Simulation of Dispersion in Urban Areas
Investigators: Parlange, Marc , Meneveau, Charles
Institution: The Johns Hopkins University
EPA Project Officer: Aja, Hayley
Project Period: October 1, 2001 through September 30, 2007
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (2001) Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management

Objective:

The dispersion of aerosols from hazardous substance incinerators has long been a concern in urban environments. The transport of aerosols in this environment is extremely complex due to the spatial variability of surface heat fluxes and topography, land-water contrasts, drainage flows at night and mesoscale weather patterns. Large Eddy Simulation (LES) is becoming a reliable modern computational method to simulate turbulence in the atmospheric boundary layer (ABL) over complex terrain.

Summary/Accomplishments (Outputs/Outcomes):

Over 50% of the world population now lives in urban areas. Improving our understanding of atmospheric flow and transport in such areas is essential. New numerical tools such as large eddy simulation (LES) are very well suited to capture the complex flow dynamics in urban canopies. A computational simulation tool was developed in this research project to address potential exposure pathways in urban environments from airborne particles. Computer simulations of air movement and pollutant transport in urban environments are especially challenging due to the complex ground topology typically found in cities. A building cluster, consisting of a group of buildings of roughly comparable size, is expected to provide the most complicated flow patterns because the flow interference among the buildings needs to be considered. The LES code considered the resolution at which buildings in cities and towns must be resolved to realistically simulate the lower atmosphere. The use and tests of the immersed boundary method for complex geometry showed that the minimum requirement for reasonably resolving the flow around a bluff body is roughly 6-8 grid points across the body. Individual buildings were resolved with at least 6 points across each building. The flow over buildings was accurately simulated with new-generation dynamic subgrid models. The buildings were well represented by the immersed boundary method; a body force represented the effect of the buildings. The simulations show that buildings greatly increase the variability of the pollutant concentration from an upstream source even high above the buildings.

One project improved our understanding of metal speciation pertinent to metal-contaminated sites.

Journal Articles on this Report : 3 Displayed | Download in RIS Format

Publications Views
Other subproject views:	All 23 publications	3 publications in selected types	All 3 journal articles
Other center views:	All 108 publications	22 publications in selected types	All 20 journal articles

Publications
Type	Citation	Sub Project	Document Sources
Journal Article	Bou-Zeid E, Meneveau C, Parlange MB. Large-eddy simulation of neutral atmospheric boundary layer flow over heterogeneous surfaces: blending height and effective surface roughness. Water Resources Research 2004;40:W02505.	R828771C004 (2004) R828771C004 (2005) R828771C004 (Final)	Abstract: AGU Abstract Exit Other: AGU PDF Exit
Journal Article	Bou-Zeid E, Meneveau C, Parlange M. A scale-dependent Lagrangian dynamic model for large eddy simulation of complex turbulent flows. Physics of Fluids 2005;17:025105.	R828771C004 (2005) R828771C004 (Final)	Abstract: AIP Abstract Exit Other: AIP PDF Exit
Journal Article	Tseng Y-H, Meneveau C, Parlange MB. Modeling flow around bluff bodies and predicting urban dispersion using large eddy simulation. Environmental Science & Technology 2006;40(8):2653-2662.	R828771C004 (Final)	Abstract from PubMed Other: American Chemical Society PDF Exit

Supplemental Keywords:

air quality, groundwater contamination, organics, metals, hyporheic zone, TOSC, TAB, outreach projects, Brownfields,, RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, Air, particulate matter, Health Risk Assessment, Risk Assessments, Physical Processes, Ecology and Ecosystems, ambient aerosol, ambient air quality, urban air, air toxics, epidemiology, human health effects, contaminant transport, air quality models, airborne particulate matter, contaminant cycling, exposure, air pollution, air sampling, environmental health effects, large eddy simulations, hazardous waste incinerators, human exposure, respiratory impact, airborne aerosols, aerosol composition, ambient particle health effects, PM, urban environment, aersol particles, aerosols, human health risk, hazardous substance contamination

Relevant Websites:

Center for Hazardous Substances in Urban Environments http://www.jhu.edu/hsrc/index.htm Exit

Progress and Final Reports:

Original Abstract

Main Center Abstract and Reports:

R828771 Center for the Study of Childhood Asthma in the Urban Environment

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R828771C001 Co-Contaminant Effects on Risk Assessment and Remediation Activities Involving Urban Sediments and Soils: Phase II
R828771C002 The Fate and Potential Bioavailability of Airborne Urban Contaminants
R828771C003 Geochemistry, Biochemistry, and Surface/Groundwater Interactions for As, Cr, Ni, Zn, and Cd with Applications to Contaminated Waterfronts
R828771C004 Large Eddy Simulation of Dispersion in Urban Areas
R828771C005 Speciation of chromium in environmental media using capillary electrophoresis with multiple wavlength UV/visible detection
R828771C006 Zero-Valent Metal Treatment of Halogenated Vapor-Phase Contaminants in SVE Offgas
R828771C007 The Center for Hazardous Substances in Urban Environments (CHSUE) Outreach Program
R828771C008 New Jersey Institute of Technology Outreach Program for EPA Region II
R828771C009 Urban Environmental Issues: Hartford Technology Transfer and Outreach
R828771C010 University of Maryland Outreach Component
R828771C011 Environmental Assessment and GIS System Development of Brownfield Sites in Baltimore
R828771C012 Solubilization of Particulate-Bound Ni(II) and Zn(II)
R828771C013 Seasonal Controls of Arsenic Transport Across the Groundwater-Surface Water Interface at a Closed Landfill Site
R828771C014 Research Needs in the EPA Regions Covered by the Center for Hazardous Substances in Urban Environments
R828771C015 Transport of Hazardous Substances Between Brownfields and the Surrounding Urban Atmosphere

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.