CFD simulation of the wind environment around an isolated high-rise building: An evaluation of SRANS, LES and DES models

Liu, Jianlin; Niu, Jianlei

doi:10.1016/j.buildenv.2015.11.007

Cited by 199 publications

(74 citation statements)

References 33 publications

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“…The size of the computational domain was 25L � 9W � 12H, and the resulting blockage ratio of the domain was 2.8% (and within the recommended limit of less than 3.0%), ensuring fully developed airflow [32][33][34]. The combined force that drives the airflow through the building was induced by the indoor-outdoor temperature difference and ambient wind.…”

Section: Geometrical Modelmentioning

confidence: 99%

“…The RANS equations govern the transport of averaged flow quantities, with an appropriate turbulence model for representing a range of turbulence scales. Compared with large eddy simulation and detached eddy simulation models, the RANS-based modeling approach significantly reduces the required computational power and resources [34,37]. Several studies have successfully employed RANS models to predict indoor and outdoor airflows in windward and leeward conditions [23,39].…”

Section: Numerical Modelmentioning

confidence: 99%

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Numerical investigation of gaseous pollutant cross-transmission for single-sided natural ventilation driven by buoyancy and wind

Wang

Huo

Zhang

et al. 2020

Building and Environment

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A B S T R A C TSingle-sided natural ventilation was numerically investigated to determine the impact of buoyancy and wind on the cross-transmission of pollution by considering six window types commonly found in multistory buildings. The goal of this study was to predict the gaseous pollutant transmission using computational fluid dynamics based on the Reynolds-averaged Navier-Stokes equations and baseline k-ω turbulence equations. The results indicated that ventilation rates generally increased with increasing wind speeds if the effects of buoyancy and wind were not suppressed; however, the re-entry ratio representing the proportion of expelled air re-entering other floors and the corresponding risk of infection decreased. If the source of the virus was on a central floor, the risk of infection was the highest on the floors closest to the source. Different window types were also considered for determining their effectiveness in controlling cross-transmission and infection risk, depending on the source location and driving force (e.g., buoyancy and wind).

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Section: Geometrical Modelmentioning

confidence: 99%

Section: Numerical Modelmentioning

confidence: 99%

Numerical investigation of gaseous pollutant cross-transmission for single-sided natural ventilation driven by buoyancy and wind

Wang

Huo

Zhang

et al. 2020

Building and Environment

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“…From the last decade, study on microclimate in a street canyon has become a hot issue focussing on ventilation, temperature, and pollutant dispersion. Numerical and experimental validation studies on street canyons indicate that ventilation is a vital element in these related indices on urban microclimate [12]. Air in the city can be well mixed and exchanged under the windy condition that introduces the fresh air from the suburbs into the city.…”

Section: Introductionmentioning

confidence: 99%

“…Stagnant air caused by poor ventilation in street canyons leads to the massive accumulation of pollutants and anthropogenic heat, exacerbating the outdoor air quality [3][4][5] and the Urban Heat Island effect (UHI) [6][7][8][9]. Outdoor environment is essential not only for people directly exposed to the circumstance [10,11], but it also has an important influence on the indoor environment [12]. From the last decade, study on microclimate in a street canyon has become a hot issue focussing on ventilation, temperature, and pollutant dispersion.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Urban Ventilation in Regulating Microclimate and Pollutant Dispersion in Urban Street Canyon: A Case Study of Nanjing New Region, China

et al. 2017

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Abstract:Urban ventilation plays an important role in regulating city climate and air quality. A numerical study was conducted to explore the ventilation effectiveness on the microclimate and pollutant removal in the urban street canyon based on the rebuilt Southern New Town region in Nanjing, China. The RNG k − ε turbulence model in the computational fluid dynamics (CFD) was employed to study the street canyon under parallel and perpendicular wind directions, respectively. Velocity inside of the street canyon and temperature on the building envelopes were obtained. A novel pressure coefficient was defined, and three methods were applied to evaluate the urban ventilation effectiveness. Results revealed that there was little comfort difference for the human body under two ventilation patterns in the street canyon. Air stagnation occurred easily in dense building clusters, especially under the perpendicular wind direction. In addition, large pressure coefficients (C P > 1) appeared at the windward region, contributing to promising ventilation. The air age was introduced to evaluate the "freshness" of the air in the street canyon and illustrated the ventilation effectiveness on the pollutant removal. It was found that the young air distributed where the corresponding ventilation was favorable and the wind speed was large. The results from this study can be useful in further city renovation for the street canyon construction and municipal planning.

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“…Detached-eddy simulation (DES) takes advantage of the Reynolds-averaged Navier-Strokes (RANS) method where mean flow is attached and steady (e.g., walls), while offering, like large-eddy simulation (LES), the sensitivity to capture unsteady flow phenomena in areas of physical interest such as wakes or recirculation zones [1][2][3][4][5]. Although this strategy is beyond the computational cost of a steady RANS calculation, it reveals nearly as much information about the flow dynamics as LES.…”

Section: Introductionmentioning

confidence: 99%

An Entropy-Assisted Shielding Function in DDES Formulation for the SST Turbulence Model

Zhou

Zhao

Shi

2017

Entropy

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Abstract:The intent of shielding functions in delayed detached-eddy simulation methods (DDES) is to preserve the wall boundary layers as Reynolds-averaged Navier-Strokes (RANS) mode, avoiding possible modeled stress depletion (MSD) or even unphysical separation due to grid refinement. An entropy function f s is introduced to construct a DDES formulation for the k-ω shear stress transport (SST) model, whose performance is extensively examined on a range of attached and separated flows (flat-plate flow, circular cylinder flow, and supersonic cavity-ramp flow). Two more forms of shielding functions are also included for comparison: one that uses the blending function F 2 of SST, the other which adopts the recalibrated shielding function f d_cor of the DDES version based on the Spalart-Allmaras (SA) model. In general, all of the shielding functions do not impair the vortex in fully separated flows. However, for flows including attached boundary layer, both F 2 and the recalibrated f d_cor are found to be too conservative to resolve the unsteady flow content. On the other side, f s is proposed on the theory of energy dissipation and independent on from any particular turbulence model, showing the generic priority by properly balancing the need of reserving the RANS modeled regions for wall boundary layers and generating the unsteady turbulent structures in detached areas.

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CFD simulation of the wind environment around an isolated high-rise building: An evaluation of SRANS, LES and DES models

Cited by 199 publications

References 33 publications

Numerical investigation of gaseous pollutant cross-transmission for single-sided natural ventilation driven by buoyancy and wind

Numerical investigation of gaseous pollutant cross-transmission for single-sided natural ventilation driven by buoyancy and wind

Numerical Study on the Urban Ventilation in Regulating Microclimate and Pollutant Dispersion in Urban Street Canyon: A Case Study of Nanjing New Region, China

An Entropy-Assisted Shielding Function in DDES Formulation for the SST Turbulence Model

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