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NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Detailed numerical modeling of local atmospheric dispersion in
an idealized urban area
M. Milliez, S. Panzarella, B. CarissimoCEREA
Research and Teaching Center for Atmospheric Environment
Chatou/Marne-la-Vallée, FRANCE
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Outline Objectives The Mercure model Simulation results evaluated with two experiments:
Hydraulic simulation of the MUST array (R.W.Macdonald, C.E.Ejim, 2002) : results and comparison
MUST: Mock Urban Setting Test (C.A.Biltoft et al., 2001) : results and preliminary comparison
Perspectives
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Objectives Investigate flows and pollution dispersion in an urban
environment: analyses of flow properties and concentration fields.
In order to: Study the impact on population and environment on a
local scale Describe the average building effects (in terms of
porosity, drag and turbulence) on flow and concentration fields
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
The Mercure model Developed by EDF and CEREA 3-D model adapted to atmospheric flow and dispersion
simulation Core of the model: CFD model Code_Saturne (EDF)
which can handle complex geometry and complex physics
Unstructured grid, finite volumes Simulations:
Eulerian approach Full scale, fine resolution, complex terrain, thermal
effects Large scale meteo. conditions taken into account k- turbulence closure model porosity/drag option
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Hydraulic simulation of the MUST array Report “Flow and Dispersion Data from a Hydraulic
Simulation of the MUST array”, R.W. Macdonald, C.E. Ejim,2002, University of Waterloo, Canada
Hydraulic flume with an upstream region to simulate of a turbulent ABL flow in neutral stability conditions.
Experiments: 1:50 scale Array of 10x4 obstacles (200mm long, 50mm wide, 50
mm high) Use of heat as a tracer
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Hydraulic simulation of the MUST array continuous release:
several locations upstream and within the array 3 different flow direction: 0 deg, 30 deg, 45 deg
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Simulations with the Mercure model Mesh: ~900 000 elements Horizontal grid = 0.5 m x
0.5m Stretched vertical grid =
0.5m -> 1.6 m
Boundary conditions: Upstream :
Dowstream: gradients = 0
2*
3*
*( ) ln( )
0
u zu z
z
uk
C
u
z
z0=0.3m
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Simulations with the Mercure model
0 ° 30 °
45 °
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
ComparisionsWind 0 °, source upstream
U TKE
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Comparisions: concentration
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Comparisions: concentration
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
The Mock Urban Setting Test C.A. Biltoft, et al. Report and data, 2001.
Near full scale experiment in the U.S. Army Dugway Proving Ground (Utah), conducted for the DTRA (Defense Thread Reduction Agency )
Objectives : acquire meteo. and dispersion data set overcome the scaling limitations of laboratories
simulations.
Neutral gas releases in a field of containers.
Array of 10x12 obstacles (12.9 m long, 2.42 m wide, 2.54 m high)
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
The Mock Urban Setting Test Releases for different meteorological conditions in
several locations within the array 63 continous releases of duration of ~15 min Data: preanalyses and statistics
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
The Mock Urban Setting TestNPneumatic Mast
simulated wind
30°
Line1 h=1.6 m
Line2 h=1.6 m
32-m Tower(digiPIDs at 1-, 2-, 4-, 6-, 8-,10-, 16-m levels)
Line5
Line4 h=1.6 m
Line3 h=1.6 m
simulated release point:
Hs=0.15 m
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Simulations with the Mercure model
Horizontal grid : lower levels
Stretched vertical grid~4 m
~2 m
0.6 to 1m
~0.3 m
~4 m
Mesh: ~800 000 hexahedral elements Dimensions: 240 m x 233 m x 32m
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Simulations with the Mercure model Boundary conditions:
Upstream :wind profile in a stable atmosphere
L=100 Z0=0.1m
Wind bearing: 28 ° u~3m/s (z=8m)
Dowstream: gradients = 0 Top : symetry and free slip
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Simulations with the Mercure model
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Simulations with the Mercure model
Y=86 mY=106 mY=146 m
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Simulations with the Mercure model
Y=86 m
Y=106 m
Y=146 m
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
First comparisons: wind speed
1
3
2
Row 5
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
First comparisons: TKE
1
3
2
Row 5
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
First comparisons: concentration
1
3
2
Row 5
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
First comparisons
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Conclusions Water flume simulations:
Satisfactory results for wind, turbulence and C at 0°
Differences in side wall effects at 30°, 45° comparison not conclusive
MUST simulations: first results : encouraging comparison further analyses needed ( inflow profile …)
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Perspectives
More analyses / comparisons with the MUST experiment
Future thesis work = take into account heat fluxes and radiative transfers with buildings
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Acknowledgments Rob Macdonald, University of Waterloo (CA)
water flume experimental data and analysis
Defense Threat Reduction Agency (USA) MUST field experiment database
B. Carissimo was supported during his sabbatical leave by the Comprehensive Atmospheric Modeling Program (CAMP) at George Mason University (USA)
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Thank you
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Maya Milliez
NATO ADVANCED STUDY INSTITUTE, Kyiv, May 2004
Simulation with the Mercure model