Development of a computational fluid dynamics model with tree drag parameterizations: Application to pedestrian wind comfort in an urban area

Kang, Geon; Kim, Jae‐Jin; Kim, Dong-Ju; Choi, Won-Sik; Park, Soo‐Jin

doi:10.1016/j.buildenv.2017.08.008

Cited by 47 publications

(31 citation statements)

References 26 publications

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“…for both or only wall A and wall B, along with values available in literature that were obtained byMoonen et al (2013) andKang et al (2017). Results show that current quality metrics mostly belong to the recommendation ranges when considering both walls A and B.…”

supporting

confidence: 58%

“…The CODASC benchmark was considered by several studies to assess the performance of different CFD approaches in predicting pollutant dispersion in the presence of trees. Studies often considered the H/W=1 configuration with a wind incidence perpendicular to the canyon axis (Gromke et al, 2008;Balczó et al, 2009;Salim et al, 2011;Moonen et al, 2013;Gromke and Blocken, 2015a;Vranckx et al, 2015;Kang et al, 2017), or the H/W=0.5…”

Section: Related Studiesmentioning

confidence: 99%

“…Nonetheless, overall, studies generally concluded that RANS approaches may constitute an acceptable compromise between prediction accuracy, applicability and computational costs. Using unsteady RANS,Kang et al (2017) found also a relatively satisfactory agreement between predictions and measurements in terms of flow and concentration patterns for the different tested tree configurations, but concentrations were underestimated for wall A and overestimated for wall B.When comparing LES to RANS, Salim et al (2011) found a substantially better performance of LES than that of RANS, especially with respect to the consistency of concentration distributions. The better performance of LES was explained by its ability to reproduce intermittent turbulent fluctuations.…”

mentioning

confidence: 90%

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Lattice-Boltzmann Large-Eddy Simulation of pollutant dispersion in street canyons including tree planting effects

Merlier

Jacob

Sagaut

2018

Atmospheric Environment

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This study assesses the performance of a large eddy simulation (LES) based on the lattice Boltzmann method (LBM) in predicting near field dispersion in street canyons with tree planting. Based on a benchmark test case benefiting from wind tunnel measurements (CODASC), this study qualitatively and quantitatively discusses the prediction of traffic-induced pollutant concentration with respect to several reference studies. It also analyses the physics of the flow and concentration fields. Although the problem might seem rather simple, the flow is highlighted to be strongly three dimensional and transient. These properties enhance pollutant dispersion in the empty street canyon but air flow velocity and turbulence intensity tend to decrease in tree crowns. This effect of trees increases both mean and peak concentration levels at pedestrian level, which may be problematic in cities with dense traffic. These results show that LBM-LES is particularly well suited to study dispersion problems towards the development of more breathable cities.

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supporting

confidence: 58%

Section: Related Studiesmentioning

confidence: 99%

mentioning

confidence: 90%

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Lattice-Boltzmann Large-Eddy Simulation of pollutant dispersion in street canyons including tree planting effects

Merlier

Jacob

Sagaut

2018

Atmospheric Environment

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“…6f) (e.g. Ashie and Kono 2011;Toparlar et al 2015Toparlar et al , 2017Toparlar et al , 2018Montazeri et al 2017;Yang et al 2017;Kang et al 2017;Gao et al 2018;Allegrini and Carmeliet 2018), urban ventilation and/or pollutant dispersion (Fig. 6g) (e.g.…”

Section: Rans In Building Simulation-outdoormentioning

confidence: 99%

LES over RANS in building simulation for outdoor and indoor applications: A foregone conclusion?

2018

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Large Eddy Simulation (LES) undeniably has the potential to provide more accurate and more reliable results than simulations based on the Reynolds-averaged Navier-Stokes (RANS) approach. However, LES entails a higher simulation complexity and a much higher computational cost. In spite of some claims made in the past decades that LES would render RANS obsolete, RANS remains widely used in both research and engineering practice. This paper attempts to answer the questions why this is the case and whether this is justified, from the viewpoint of building simulation, both for outdoor and indoor applications. First, the governing equations and a brief overview of the history of LES and RANS are presented. Next, relevant highlights from some previous position papers on LES versus RANS are provided. Given their importance, the availability or unavailability of best practice guidelines is outlined. Subsequently, why RANS is still frequently used and whether this is justified or not is illustrated by examples for five application areas in building simulation: pedestrian-level wind comfort, near-field pollutant dispersion, urban thermal environment, natural ventilation of buildings and indoor airflow. It is shown that the answers vary depending on the application area but also depending on other-less obvious-parameters such as the building configuration under study. Finally, a discussion and conclusions including perspectives on the future of LES and RANS in building simulation are provided.

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“…Many studies are available in the literature and best practice guidelines [13][14][15] on the use of CFD for that kind of application have been proposed. Most of existing CFD simulations have been performed using the Reynolds Average Navier Stokes (RANS) approach, which resolves only the mean, time-averaged flow while the turbulent motion is modelled, on simplified [16][17][18][19] or realistic [18,[20][21][22][23][24][25][26][27][28][29] geometries. However time-resolved approaches such as Detached Eddy Simulation (DES, see Ref.…”

Section: Introductionmentioning

confidence: 99%

Wind comfort assessment by means of large eddy simulation with lattice Boltzmann method in full scale city area

Jacob

Sagaut

2018

Building and Environment

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Large-eddy simulations based on the Lattice-Boltzmann method of the flow in a realistic, full scale urban area are performed to compare several wind comfort criteria. It is observed that popular criteria for pedestrian comfort lead to very different conclusions, due to the access to high spatio-temporal resolution data. Different mixed strategies based on the combination of several criteria are proposed and compared to enhance pedestrian wind comfort assessment in practical cases.

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Development of a computational fluid dynamics model with tree drag parameterizations: Application to pedestrian wind comfort in an urban area

Cited by 47 publications

References 26 publications

Lattice-Boltzmann Large-Eddy Simulation of pollutant dispersion in street canyons including tree planting effects

Lattice-Boltzmann Large-Eddy Simulation of pollutant dispersion in street canyons including tree planting effects

LES over RANS in building simulation for outdoor and indoor applications: A foregone conclusion?

Wind comfort assessment by means of large eddy simulation with lattice Boltzmann method in full scale city area

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