Influence of avenue-trees on air quality at the urban neighborhood scale. Part I: Quality assurance studies and turbulent Schmidt number analysis for RANS CFD simulations

Gromke, CB Christof; Blocken, Bje Bert

doi:10.1016/j.envpol.2014.10.016

Cited by 136 publications

(48 citation statements)

References 60 publications

(88 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…All tree crowns are modeled with a vertically uniform profile of leaf area density (LAD) which was set to LAD ¼ 1 m 2 m À3 and the leaf drag coefficient (C d ) was set to C d ¼ 0.2, see Eqs. (4)e(6) in Part I (Gromke and Blocken, 2014). As already mentioned in Part I, these values can be considered typical for deciduous trees commonly found in urban street canyons.…”

Section: Methodsmentioning

confidence: 57%

“…Notice that due to symmetric boundary conditions only half of the total pedestrian level is shown (see Fig. 1 in Gromke and Blocken, 2014). In the wind-parallel streets (row 2, 4, 6) a continuous concentration build-up in the windward first canyons is present until the Fig.…”

Section: Methodsmentioning

confidence: 97%

“…The urban neighborhood together with an outline of the computational domain and the numerical setting as well as a description of the vegetation model are given in Section 2 of Part I (Gromke and Blocken, 2014) of this two-part contribution. Here, an overview of the scenarios with different avenue-tree layouts in the urban neighborhood is provided in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Common to scenarios 2 to 8 is that the tree rows consisting of crowns of 6 m width and 12 m height, starting 6 m above the street level, are always positioned horizontally centered in the street canyon sections of width W ¼ 18 m, height H ¼ 30 m and length L ¼ 90 m, see Fig. 1 in Part I (Gromke and Blocken, 2014). All tree crowns are modeled with a vertically uniform profile of leaf area density (LAD) which was set to LAD ¼ 1 m 2 m À3 and the leaf drag coefficient (C d ) was set to C d ¼ 0.2, see Eqs.…”

Section: Methodsmentioning

confidence: 99%

“…The study is the second of a two-part contribution. The companion paper, Part I (Gromke and Blocken, 2014), introduces the generic urban neighborhood, its layout and the computational domain, and describes the numerical methods and settings. Furthermore, it details quality assessment and assurance studies which were performed to guarantee reliable CFD simulations of flow and pollutant dispersion in the urban environment with avenue-trees.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

Self Cite

133

View full text Add to dashboard Cite

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.

show abstract

Section: Methodsmentioning

confidence: 57%

Section: Methodsmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Self Cite

133

View full text Add to dashboard Cite

show abstract

Reconstruction of an atmospheric tracer source in an urban‐like environment

et al. 2015

View full text Add to dashboard Cite

This study describes a methodology combining a recently proposed renormalization inversion technique with a building‐resolving computational fluid dynamics (CFD) approach for source retrieval in the geometrically complex urban regions. It presents the first application of the renormalization inversion approach to estimate an unknown continuous point release in real situations at an urban scale. The renormalization inversion approach is based on an adjoint source‐receptor relationship and is purely deterministic in nature. The source parameters (i.e., source location and release rate) are reconstructed from a finite set of point measurements of concentration acquired from some sensors and the adjoint functions computed from a CFD model fluidyn‐PANACHE that is able to represent the geometric and flow complexity inherent in the urban regions. The inversion procedure is evaluated for a point source reconstruction using measurements from the Mock Urban Setting Test (MUST) field experiment. Source reconstructions are performed for 20 trials of the MUST experiment of a continuous point release in an idealized urban geometry consisting of a regular array of shipping containers. The steady state flow fields are computed by solving the three‐dimensional Reynolds‐averaged Navier‐Stokes equations by using a finite volume scheme. Then, in each MUST trial adjoint functions are obtained and used for the source identification. Inversion results are presented with both synthetic and real measurements in various atmospheric stabilities varying from neutral to stable and very stable conditions. With real concentration measurements, the point source is retrieved within an average Euclidean distance of 14.6 m from the actual source location. The estimated source intensity is overpredicted by an average factor of 1.37 of the true release rate. In a posterior uncertainty analysis with 10% random noise in measurements, it is demonstrated that standard deviation in the location error and release strength, respectively, varies by 5.22 m and ∼21% from their mean value for all 20 trials. A sensitivity analysis shows that the use of nonzero measurements helps in reducing the uncertainties involved in the source reconstruction. The source reconstruction results in various stability conditions exhibit the reliability of the renormalization inversion methodology coupled with the CFD approach in an urban area. The present methodology can be used by emergency regulators as a tool to detect the unknown accidental or deliberated releases in the complex urban environments.

show abstract

An impact of Richardson number on the inclined MHD mixed convective flow with heat and mass transfer

Mahabaleshwar,

Anusha,

Sachhin

et al. 2024

Heat Trans

View full text Add to dashboard Cite

The two‐dimensional mixed convective MHD flow with heat and mass transfer is investigated for its behavior with Dufour and Soret mechanisms over the porous sheet. The copper–alumina (Cu–Al2O3) hybrid nanoparticles are used in the base fluid water. The governing system of partial differential equations is converted into a system of ordinary differential equations via similarity transformations, obtaining the solution for velocity, temperature, and concentration fields in exponential form. The problem is demonstrated in the Darcy–Brinkman model, the impact of included parameters such as Richardson number, magnetic field, and Dufour numbers are studied for the obtained solution with the help of graphs. Increasing the magnetic field decreases both transverse and axial velocity profiles. Increasing the magnetic field and Richardson's number decreases the solution (Al2O3–H2O). Increasing the values magnetic field and Richardson's number decreases both transverse and axial velocity profiles. Increasing the values of the Dufour effect increases the axial and transverse velocity boundary layer. The magnetohydrodynamic hybrid nanofluid flow over porous media works efficiently in liquid cooling and, therefore, has significant applications in industrial heating and cooling systems, solar energy, magnetohydrodynamic flow meters and pumps, manufacturing, regenerative heat exchange, thermal energy storage, solar power collectors, geothermal recovery, and chemical catalytic reactors.

show abstract

Influence of avenue-trees on air quality at the urban neighborhood scale. Part I: Quality assurance studies and turbulent Schmidt number analysis for RANS CFD simulations

Cited by 136 publications

References 60 publications

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

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

Reconstruction of an atmospheric tracer source in an urban‐like environment

An impact of Richardson number on the inclined MHD mixed convective flow with heat and mass transfer

Contact Info

Product

Resources

About