Large-Eddy Simulation of Dispersion from Surface Sources in Arrays of Obstacles

Boppana, V. B. L.; Xie, Zheng-Tong; Castro, Ian P.

doi:10.1007/s10546-010-9489-9

Cited by 74 publications

(31 citation statements)

References 33 publications

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“…It seems that no consensus exists in the literature on any particular value, considering the various values that can be found, e.g. 0.5 in [54], 0.6 in [55], 0.72 in [56] or 0.9 in [57].…”

Section: Mass Fluxesmentioning

confidence: 99%

Near-field pollutant dispersion in an actual urban area: Analysis of the mass transport mechanism by high-resolution Large Eddy Simulations

et al. 2015

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Graphical abstractHighlights -Pollutant dispersion in downtown Montreal is studied with high-resolution LES.-The contribution of the sub-grid scales to turbulent mass transport is minor in this case.-The results of this applied case are linked to those obtained for a generic isolated building.-The counter gradient mechanism of turbulent mass transport is observed.-With RANS, the turbulent flux model used should be able to reproduce this mechanism. AbstractLarge-Eddy Simulation of near-field pollutant dispersion from stacks on the roof of a low-rise building in downtown Montreal is performed. Two wind directions are considered, with different wind-flow patterns and plume behavior. The computed mean concentration field is analyzed by means of the convective and turbulent (including subgrid-scale) mass fluxes. This decomposition provides insight into the dispersion process and allows an evaluation of common turbulent transport models used with the Reynolds-Averaged Navier-Stokes approach, such as the standard gradient-diffusion hypothesis. Despite the specific character of the flow and dispersion patterns due to the complex geometry of the urban area under study, some similarities are found with the generic case of dispersion around an isolated simple building. Moreover, the analysis of dispersion in downtown Montreal is facilitated by the physical insight gained by the study of the generic case. In this sense, the present study supports the use of generic, simplified cases to investigate and understand environmental processes as they occur in real and more complex situations. Reciprocally, the results of this applied study show the influence on the dispersion process of the rooftop structures and of the orientation of the emitting building with respect to the incoming wind flow, providing directions for further research on generic cases.

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“…It seems that no consensus exists in the literature on any particular value, considering the various values that can be found, e.g. 0.5 in [54], 0.6 in [55], 0.72 in [56] or 0.9 in [57].…”

Section: Mass Fluxesmentioning

confidence: 99%

Near-field pollutant dispersion in an actual urban area: Analysis of the mass transport mechanism by high-resolution Large Eddy Simulations

et al. 2015

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“…Recently, research has been undertaken to study dispersion and ventilation in actual or generic building block arrays with tree-free streets (e.g. Boppana et al, 2010;Borrego et al, 2006Borrego et al, , 2003Buccolieri et al, 2010;Carpentieri et al, 2012;Di Sabatino et al, 2007;Garbero et al, 2010;Hamlyn et al, 2007;Hang et al, 2011;Panagiotou et al, 2013;Pascheke et al, 2008;Princevac et al, 2010;Ramponi et al, 2014;Soulhac et al, 2012Soulhac et al, , 2011Soulhac et al, , 2003Xie and Castro, 2009). It is evident that such study areas provide a more relevant description of the effects of trees on flow and pollutant dispersion than those with isolated street canyons or intersections.…”

Section: Introductionmentioning

confidence: 99%

Influence of avenue-trees on air quality at the urban neighborhood scale. Part II: Traffic pollutant concentrations at pedestrian level

Gromke

Blocken

2015

Environmental Pollution

139

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a b s t r a c tFlow and dispersion of traffic-emitted pollutants were studied in a generic urban neighborhood for various avenue-tree layouts by employing 3D steady RANS simulations with the realizable k-ε turbulence model. In comparison to the tree-free situation quantitative and qualitative changes with flow reversal in the wind field were observed. Low to moderate increases (<13.2%) in the neighborhood-averaged pollutant concentration were found at pedestrian level. An approximately 1% increase in the neighborhood-averaged concentration was obtained with each percent of the street canyon volumes being occupied by vegetation for occupation fractions between 4 and 14%. The overall pattern of concentration changes relative to the tree-free situation was similar for all avenue-tree layouts. However, pronounced locally restricted decreases or increases in concentration (À87 to þ1378%) occurred. The results indicate the necessity to account for existing or planned avenue-trees in neighborhood scale dispersion studies. Their consideration is prerequisite for reliable urban air quality assessment.

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“…Xie and Castro, 2008). Before studying typical street-scale dispersion using LES (with results discussed in Xie and Castro, 2009;Boppana et al, 2010) we addressed the conceptually simpler case of scalar dispersion in a channel flow, largely because there are some existent laboratory experiments and direct numerical simulations (DNS) for such flows; it is this topic that is discussed in the present paper.…”

Section: Introductionmentioning

confidence: 99%

Large-Eddy Simulation of Dispersion from Line Sources in a Turbulent Channel Flow

Boppana

Xie

Castro

2011

Flow Turbulence Combust

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Large-eddy simulations of the dispersion from scalar line sources at various locations within a fully developed turbulent channel flow at Re = uh/ν = 10400 are presented. Both mean and fluctuating scalar quantities are compared with those from the single available set of experimental data (Lavertu and Mydlarski, 2005) and differences are highlighted and discussed. The results are also discussed in the context of scalar dispersion in other kinds of turbulent flows, e.g. homogeneous shear-flow. Initial computations at a much lower Reynolds number are also reported and compared with the two available direct numerical simulation data sets.

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Large-Eddy Simulation of Dispersion from Surface Sources in Arrays of Obstacles

Cited by 74 publications

References 33 publications

Near-field pollutant dispersion in an actual urban area: Analysis of the mass transport mechanism by high-resolution Large Eddy Simulations

Near-field pollutant dispersion in an actual urban area: Analysis of the mass transport mechanism by high-resolution Large Eddy Simulations

Influence of avenue-trees on air quality at the urban neighborhood scale. Part II: Traffic pollutant concentrations at pedestrian level

Large-Eddy Simulation of Dispersion from Line Sources in a Turbulent Channel Flow

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