A numerical study of atmospheric pollutant dispersion in different two-dimensional street canyon configurations

Assimakopoulos, Vasiliki D.; ApSimon, Helen; Moussiopoulos, Ν.

doi:10.1016/s1352-2310(03)00533-8

Cited by 136 publications

(75 citation statements)

References 19 publications

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“…Thus, the calculations established the connection between horizontal roof level wind and the flow field inside the canyon (Voigtländer, 2005). The typical circulation in a regular street canyon can be found in literature (e.g., Scaperdas and Colville, 1998;Assimakopoulos et al, 2003;Nazridoust and Ahmadi, 2006). Traffic exhaust from street is directly transported to the lee side building of the street canyon.…”

Section: Discussionmentioning

confidence: 97%

“…In regular street canyons (height to width ratio in roughly unity, Vardoulakis et al, 2003), one large vortex can be found. In deeper canyons, a weaker second (and a third) vortex can be observed and modeled (Assimakopoulos et al, 2003) and in wide canyons (height to width ratio below approx. 0.5) no recirculation vortex is observed.…”

Section: Introductionmentioning

confidence: 97%

“…With high traffic volume at ground level, the circulation leads to higher concentrations in the lee side of the street and lower concentrations in the luff (e.g., Assimakopoulos et al, 2003). At the top of the canyon, turbulent processes mix urban background air into the canyon (Baik and Kim, 2002), which causes a lower concentration at the luff side building.…”

Section: Introductionmentioning

confidence: 99%

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Correlation between traffic density and particle size distribution in a street canyon and the dependence on wind direction

et al. 2006

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Abstract. Combustion of fossil fuel in gasoline and diesel powered vehicles is a major source of aerosol particles in a city. In a street canyon, the number concentration of particles smaller than 300 nm in diameter, which can be inhaled and cause serious health effects, is dominated by particles originating from this source.In this study we measured both, particle number size distribution and traffic density continuously in a characteristic street canyon in Germany for a time period of 6 months. The street canyon with multistory buildings and 4 traffic lanes is very typical for larger cities. Thus, the measurements also are representative for many other street canyons in Europe. In contrast to previous studies, we measured and analyzed the particle number size distribution with high size resolution using a Twin Differential Mobility Analyzer (TDMPS). The measured size range was from 3 to 800 nm, separated into 40 size channels.Correlation coefficients between particle number concentration for integrated size ranges and traffic counts of 0.5 were determined. Correlations were also calculated for each of the 40 size channels of the DMPS system, respectively. We found a maximum of the correlation coefficients for nucleation mode particles in the size range between 10 and 20 nm in diameter.Furthermore, correlations between traffic and particles in dependence of meteorological data were calculated. Relevant parameters were identified by a multiple regression method. In our experiment only wind parameters have influenced the particle number concentration significantly. High correlation coefficients (up to 0.8) could be observed in the lee side of the street canyon for particles in the range between 10 and 100 nm in diameter. These values are significantly higher than correlation coefficients for other wind directions and other particle sizes. A minimum was found in the luff Correspondence to: J. Voigtländer (jensv@tropos.de) side of the street. These findings are in good agreement with theory of fluid dynamics in street canyons.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Correlation between traffic density and particle size distribution in a street canyon and the dependence on wind direction

et al. 2006

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“…In all these 57 studies, streets are assumed to be symmetrical and homogeneous and are simplified significantly both 58 in physical models and in simulations; the resulting air flow patterns, including a persistent vortex 59 formation in the street, are found to be very unfavourable for ventilation and pollution removal. Yet in 60 a numerical study of an asymmetric canyon, Assimakopoulos et al (2003) noted that in complex 61 geometries, such as heterogeneous canyons, the flow field could significantly differ from the flow in a 62 symmetrical, homogeneous street canyon 63…”

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confidence: 99%

Air flow and pollution in a real, heterogeneous urban street canyon: A field and laboratory study

Karra

Malki-Epshtein

Neophytou

2017

Atmospheric Environment

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“…is parameter has already been investigated in other works [62,[72][73][74][75][76][77] for 2D ows, while useful insights into the e ects of building height variations for arrays of 3D buildings have recently been reported in [78][79][80]. e additional analysis we provide here focuses on the combined e ect of the variability of both building heights and AR.…”

Section: E Ect Of Building Height Variationsmentioning

confidence: 95%

CFD Analysis of Urban Canopy Flows Employing the V2F Model: Impact of Different Aspect Ratios and Relative Heights

Nardecchia

Bernardino

Pagliaro

et al. 2018

Advances in Meteorology

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Computational fluid dynamics (CFD) is currently used in the environmental field to simulate flow and dispersion of pollutants around buildings. However, the closure assumptions of the turbulence usually employed in CFD codes are not always physically based and adequate for all the flow regimes relating to practical applications. e starting point of this work is the performance assessment of the V2F (i.e., v 2 − f ) model implemented in Ansys Fluent for simulating the flow field in an idealized array of twodimensional canyons. e V2F model has been used in the past to predict low-speed and wall-bounded flows, but it has never been used to simulate airflows in urban street canyons. e numerical results are validated against experimental data collected in the water channel and compared with other turbulence models incorporated in Ansys Fluent (i.e., variations of both k-ε and k-ω models and the Reynolds stress model). e results show that the V2F model provides the best prediction of the flow field for two flow regimes commonly found in urban canopies. e V2F model is also employed to quantify the air-exchange rate (ACH) for a series of two-dimensional building arrangements, such as step-up and step-down configurations, having different aspect ratios and relative heights of the buildings. e results show a clear dependence of the ACH on the latter two parameters and highlight the role played by the turbulence in the exchange of air mass, particularly important for the step-down configurations, when the ventilation associated with the mean flow is generally poor.

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A numerical study of atmospheric pollutant dispersion in different two-dimensional street canyon configurations

Cited by 136 publications

References 19 publications

Correlation between traffic density and particle size distribution in a street canyon and the dependence on wind direction

Correlation between traffic density and particle size distribution in a street canyon and the dependence on wind direction

Air flow and pollution in a real, heterogeneous urban street canyon: A field and laboratory study

CFD Analysis of Urban Canopy Flows Employing the V2F Model: Impact of Different Aspect Ratios and Relative Heights

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