Numerical analysis of diffusion around a suspended expressway by a multi-scale CFD model

Kumakura, Hiroaki; Asahi, Kazutake; Tomizuka, Takayuki; Suzuki, Motoo

doi:10.1016/j.atmosenv.2006.01.012

Cited by 26 publications

(10 citation statements)

References 15 publications

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“…Although better accuracy can be achieved using LES and DNS [41], the application of these schemes is computationally very expensive. Instead, RANS (e. g. ke3 and k À l) is widely used for turbulent modeling in UHI studies due to its lower computational cost [31,77]. However, this scheme does not physically show good performance in simulation of the building canopies, especially inside the wake region [72].…”

Section: Turbulence Treatmentmentioning

confidence: 98%

Approaches to study Urban Heat Island – Abilities and limitations

Mirzaei

Haghighat

2010

Building and Environment

609

305

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Section: Turbulence Treatmentmentioning

confidence: 98%

Approaches to study Urban Heat Island – Abilities and limitations

Mirzaei

Haghighat

2010

Building and Environment

609

305

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“…In RANS computations, this is comparatively simple since turbulent statistics can directly be given at the boundary (Kondo et al, 2006;Baik et al, 2009). On the other hand, LES is accompanied by difficulty, because the process needs to be provided with physically appropriate temporal and spatial fluctuations.…”

Section: Inflow Boundary Conditionmentioning

confidence: 99%

CFD simulation of near-field pollutant dispersion in the urban environment: A review of current modeling techniques

Tominaga

Stathopoulos

2013

Atmospheric Environment

419

158

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h i g h l i g h t s CFD simulations of near-field dispersion in the urban environment are reviewed. Key features of near-field pollutant dispersion are identified and discussed. To understand inherent strengths and limitations of numerical models is important. Careful model evaluation while paying attention to their uncertainty is necessary. a b s t r a c tNear-field pollutant dispersion in the urban environment involves the interaction of a plume and the flow field perturbed by building obstacles. In the past two decades, micro-scale Computational Fluid Dynamics (CFD) simulation of pollutant dispersion around buildings and in urban areas has been widely used, sometimes in lieu of wind tunnel testing. This paper reviews current modeling techniques in CFD simulation of near-field pollutant dispersion in urban environments and discusses the findings to give insight into future applications. Key features of near-field pollutant dispersion around buildings from previous studies, i.e., three-dimensionality of mean flow, unsteadiness of large-scale flow structure, and anisotropy of turbulent scalar fluxes, are identified and discussed. This review highlights that it is important to choose appropriate numerical models and boundary conditions by understanding their inherent strengths and limitations. Furthermore, the importance of model evaluation was emphasized. Because pollutant concentrations around buildings can vary by orders of magnitudes in time and space, the model evaluation should be performed carefully, while paying attention to their uncertainty. Although CFD has significant potential, it is important to understand the underlying theory and limitations of a model in order to appropriately investigate the dispersion phenomena in question.

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“…Compared with applied studies focusing on wind performance in real urban morphologies [23,36,37], the current study uses the parametric approach to obtain the natural ventilation performance with generic building configurations. In the parametric study, cross-comparing the effects of different design issues is easier by observing changes in natural ventilation performance in different testing scenarios, thus identifying the critical design issues.…”

Section: Study Method: Parametric Studymentioning

confidence: 99%

Building porosity for better urban ventilation in high-density cities – A computational parametric study

Yuan

2012

Building and Environment

216

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a b s t r a c tShape-edged buildings impose large frictional drag on the flow in the urban boundary layer. In the subtropics, especially during hot and humid summers, compact building blocks create stagnant air that worsens outdoor urban thermal comfort. The current study adapts the keu SST turbulence model to simulate air flow in urban areas. The accuracy of the keu SST turbulence model in detecting air flow around a rectangular block is validated by comparing it with the data from the wind tunnel experiment. In the computational parametric study, wind speed classification is derived based on Physiological Equivalent Temperature (PET) to evaluate the effect of wind speed on outdoor thermal comfort. Numerical analysis compares the effects of different building morphology modifications on pedestrianlevel natural ventilation. Critical design issues are also identified. From both the accuracy and practical points of view, the current study allows city planners and architects to improve building porosity efficiently for better pedestrian-level urban ventilation, without losing land use efficacy.

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Numerical analysis of diffusion around a suspended expressway by a multi-scale CFD model

Cited by 26 publications

References 15 publications

Approaches to study Urban Heat Island – Abilities and limitations

Approaches to study Urban Heat Island – Abilities and limitations

CFD simulation of near-field pollutant dispersion in the urban environment: A review of current modeling techniques

Building porosity for better urban ventilation in high-density cities – A computational parametric study

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