Abstract
Poor air quality in cities was indicated as the cause of seven million deaths, one out of eight globally, only in 2012. Urban streets are the epicentre of the problem, as high concentrations are frequently measured, caused mainly by the traffic and secondly by the general urban background pollution. The flow inside street canyons has some specific characteristics that tend to obstruct the removal of pollutants from the city level. The small scale models that are used to study pollution in streets have to consider about these flow patterns, which many times are referred with the collective term recirculation zone. Our main hypothesis is, that the flow regime in a street canyon governs the recirculation zone and consequently the dispersion. Thus, a quasi-universal expression for the recirculation zone could expand the applicability of these simple models in cases of higher complexity. To understand better the recirculation zone, CFD simulations are validated and used. We use vortex detection methods, namely vorticity, streamlines and the λ2 and Q criteria, to visualize the vortex structures. The final results are rather inconclusive, although the combined use of the above methods certainly give some insights to the flow structure. In any case more exploratory analysis is necessary in order to validate the further develop the hypothesis of this work.
| Original language | English |
|---|---|
| Title of host publication | HARMO 2016 - 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings |
| Publisher | Hungarian Meteorological Service |
| Pages | 319-323 |
| Number of pages | 5 |
| Volume | 2016-May |
| ISBN (Electronic) | 9789639931107 |
| Publication status | Published - 1 Jan 2016 |
| Event | 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, HARMO 2016 - Budapest, Hungary Duration: 9 May 2016 → 12 May 2016 |
Other
| Other | 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, HARMO 2016 |
|---|---|
| Country | Hungary |
| City | Budapest |
| Period | 9/5/16 → 12/5/16 |
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Keywords
- Air quality models
- Large Eddy Simulation
- Recirculation zone
- Street canyon
- Vortex detection
ASJC Scopus subject areas
- Atmospheric Science
- Pollution
- Modelling and Simulation
Cite this
Modelling the recirculation zone in street canyons with different aspect ratios, using cfd simulation. / Chatzimichailidis, Arsenios; Assael, Marc; Ketzel, Matthias; Kakosimos, Konstantinos.
HARMO 2016 - 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings. Vol. 2016-May Hungarian Meteorological Service, 2016. p. 319-323.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Modelling the recirculation zone in street canyons with different aspect ratios, using cfd simulation
AU - Chatzimichailidis, Arsenios
AU - Assael, Marc
AU - Ketzel, Matthias
AU - Kakosimos, Konstantinos
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Poor air quality in cities was indicated as the cause of seven million deaths, one out of eight globally, only in 2012. Urban streets are the epicentre of the problem, as high concentrations are frequently measured, caused mainly by the traffic and secondly by the general urban background pollution. The flow inside street canyons has some specific characteristics that tend to obstruct the removal of pollutants from the city level. The small scale models that are used to study pollution in streets have to consider about these flow patterns, which many times are referred with the collective term recirculation zone. Our main hypothesis is, that the flow regime in a street canyon governs the recirculation zone and consequently the dispersion. Thus, a quasi-universal expression for the recirculation zone could expand the applicability of these simple models in cases of higher complexity. To understand better the recirculation zone, CFD simulations are validated and used. We use vortex detection methods, namely vorticity, streamlines and the λ2 and Q criteria, to visualize the vortex structures. The final results are rather inconclusive, although the combined use of the above methods certainly give some insights to the flow structure. In any case more exploratory analysis is necessary in order to validate the further develop the hypothesis of this work.
AB - Poor air quality in cities was indicated as the cause of seven million deaths, one out of eight globally, only in 2012. Urban streets are the epicentre of the problem, as high concentrations are frequently measured, caused mainly by the traffic and secondly by the general urban background pollution. The flow inside street canyons has some specific characteristics that tend to obstruct the removal of pollutants from the city level. The small scale models that are used to study pollution in streets have to consider about these flow patterns, which many times are referred with the collective term recirculation zone. Our main hypothesis is, that the flow regime in a street canyon governs the recirculation zone and consequently the dispersion. Thus, a quasi-universal expression for the recirculation zone could expand the applicability of these simple models in cases of higher complexity. To understand better the recirculation zone, CFD simulations are validated and used. We use vortex detection methods, namely vorticity, streamlines and the λ2 and Q criteria, to visualize the vortex structures. The final results are rather inconclusive, although the combined use of the above methods certainly give some insights to the flow structure. In any case more exploratory analysis is necessary in order to validate the further develop the hypothesis of this work.
KW - Air quality models
KW - Large Eddy Simulation
KW - Recirculation zone
KW - Street canyon
KW - Vortex detection
UR - http://www.scopus.com/inward/record.url?scp=85047225690&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85047225690&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85047225690
VL - 2016-May
SP - 319
EP - 323
BT - HARMO 2016 - 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings
PB - Hungarian Meteorological Service
ER -