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Conference Paper: Pollutant dispersion over two-dimensional idealized street canyons: a large-eddy simulation approach
Title | Pollutant dispersion over two-dimensional idealized street canyons: a large-eddy simulation approach |
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Authors | |
Keywords | LES Urban roughness Urban street canyon |
Issue Date | 2011 |
Citation | The 14th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes (HARMO14), Kos, Greece, 2-6 October 2011. In Conference Proceedings, 2011, p. 524-528 How to Cite? |
Abstract | A series of two-dimensional (2D) street canyon models with a wide range of building-height-to-street-width (aspect) ratios are employed in this study to elucidate the pollutant transport over idealized urban areas. The large-eddy simulation (LES) is used to resolve the turbulent flows and pollutant transport in the urban boundary layer (UBL) over the street canyons. An area source of uniform pollutant concentration is applied on the ground of the first street canyon to examine the pollutant plume dispersion behaviors over the downstream building roughness elements. The LES results show that, for the street canyon with the pollutant source, the pollutant removal is governed by atmospheric turbulence in both skimming flow and wake-interference regimes. Statistical analysis reveals that the turbulent kinetic energy (TKE) is peaked near the top of the building roughness elements that contributes most to turbulent pollutant removal. The roof-level TKE distribution also demonstrates that the turbulence production is not governed by local wind shear. Instead, the descending TKE from the UBL plays a more important role. In the UBL, the vertical pollutant profiles illustrate self-similarity behaviours in the downstream region. The pollutant disperses rapidly over the buildings, exhibiting a Gaussian-plume shape. Maximum vertical pollutant dispersion coefficient is observed at aspect ratio equal to 1/10. A strong correlation between friction factor and dispersion coefficient is found, implying that the downstream air quality could be improved by increasing the roughness of urban area. |
Description | Session: H14-117 |
Persistent Identifier | http://hdl.handle.net/10722/165402 |
DC Field | Value | Language |
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dc.contributor.author | Wong, CCC | en_US |
dc.contributor.author | Liu, CH | en_US |
dc.date.accessioned | 2012-09-20T08:17:54Z | - |
dc.date.available | 2012-09-20T08:17:54Z | - |
dc.date.issued | 2011 | en_US |
dc.identifier.citation | The 14th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes (HARMO14), Kos, Greece, 2-6 October 2011. In Conference Proceedings, 2011, p. 524-528 | en_US |
dc.identifier.uri | http://hdl.handle.net/10722/165402 | - |
dc.description | Session: H14-117 | - |
dc.description.abstract | A series of two-dimensional (2D) street canyon models with a wide range of building-height-to-street-width (aspect) ratios are employed in this study to elucidate the pollutant transport over idealized urban areas. The large-eddy simulation (LES) is used to resolve the turbulent flows and pollutant transport in the urban boundary layer (UBL) over the street canyons. An area source of uniform pollutant concentration is applied on the ground of the first street canyon to examine the pollutant plume dispersion behaviors over the downstream building roughness elements. The LES results show that, for the street canyon with the pollutant source, the pollutant removal is governed by atmospheric turbulence in both skimming flow and wake-interference regimes. Statistical analysis reveals that the turbulent kinetic energy (TKE) is peaked near the top of the building roughness elements that contributes most to turbulent pollutant removal. The roof-level TKE distribution also demonstrates that the turbulence production is not governed by local wind shear. Instead, the descending TKE from the UBL plays a more important role. In the UBL, the vertical pollutant profiles illustrate self-similarity behaviours in the downstream region. The pollutant disperses rapidly over the buildings, exhibiting a Gaussian-plume shape. Maximum vertical pollutant dispersion coefficient is observed at aspect ratio equal to 1/10. A strong correlation between friction factor and dispersion coefficient is found, implying that the downstream air quality could be improved by increasing the roughness of urban area. | - |
dc.language | eng | en_US |
dc.relation.ispartof | 14th HARMO International Conference Proceedings | en_US |
dc.subject | LES | - |
dc.subject | Urban roughness | - |
dc.subject | Urban street canyon | - |
dc.title | Pollutant dispersion over two-dimensional idealized street canyons: a large-eddy simulation approach | en_US |
dc.type | Conference_Paper | en_US |
dc.identifier.email | Wong, CCC: ching167kee@hotmail.com | en_US |
dc.identifier.email | Liu, CH: chliu@hkucc.hku.hk | - |
dc.identifier.authority | Liu, CH=rp00152 | en_US |
dc.description.nature | postprint | - |
dc.identifier.hkuros | 208121 | en_US |
dc.identifier.spage | 524 | - |
dc.identifier.epage | 528 | - |