Wind tunnel modelling of atmospheric boundary layer flow over hills
Tunnel modelling : the collaboration with the CETU
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Transcript of Tunnel modelling : the collaboration with the CETU
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B. Carissimo, S. Lacour, H. Foudhil,L. Musson-Genon, E. Dupont, M. Milliez, B. Albriet, E. Demael,
L. Laporte,
Tunnel modelling :
the collaboration with the CETU
Atmospheric CFD modelling for environmental applications
at local scale,
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History
• CETU: ventilation and environment team
• Technical service of the Equipment Ministry
• Defining state of art, methods for studying tunnels
• Conception of fire protection system
• Environmental studies around tunnels
Collaboration with the CEREA started in 2002
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Modelling tools
Polair3D local: • RACM chemistry• Eulerian advection diffusion scheme
Reactive plume/box models• Street model, OSPM …
Mercure_Saturne reactive version
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Dispersion around a tunnel portal Vehicle induces flows in a non-ventilated tunnel.
HVG passing produced a high frequency signal on flow velocity
Tunnel also filters vehicle drag effect and produced low frequency variations on the flow velocity
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Dispersion around a tunnel portal
Pollutant escape occurs earlier in the street in the case of unsteady flows
Advection effects were found greater than turbulent ones.
Street concentration decrease is lower than 30% in unsteady cases
Lacour and al., UAQ 2003
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Dispersion around a tunnel portal Street NO2 concentration increases
From 0% when the primary background pollution is high
Up to 100 % in case of ozone peaks
Ozone availability is a limitation factor for NO conversion near the exit
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Dispersion around a tunnel portal Statistical analysis were made for 2 different urban aeras
Reactive models (OPSM1, OSPM2, TNO, Street) were compared
Dilution factors were established for NO2 reactive dispersion around tunnel portal
Guide méthodologique « Etude d’environnement » CETU 2005
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Dispersion around a tunnel portal
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Dispersion around a tunnel portal Building affects plume geometry in this campaign
The validation of the CEREA model, developed for flat terrain, is not possible with these measurements.
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Dispersion around a tunnel portal
NO2 concentration field
wind
Reactive NO2 model was used to study depollution effectiveness of catalytic walls.
A measurement campaign would be carried out by the CETE of Lille around a tunnel portal in Paris and used for validation purposes