Wind tunnel study of turbulent flow past an urban canyon model

Marciotto, Edson R.; Fisch, Gilberto

doi:10.1007/s10652-013-9268-5

Cited by 8 publications

(6 citation statements)

References 21 publications

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“…7b). Salizzoni et al [31] also confirm this pattern, but Marciotto and Fisch [22] found that the shear stress is not dependent on λp. 3D configurations of aligned and staggered arrays show, that in both cases, an increase in λp results in an increase in the shear stress [3].…”

Section: Spatially Averaged Turbulence Statisticsmentioning

confidence: 88%

“…However, it was determined that the relationship between λp and turbulence statistics is insignificant for aligned arrays above the roughness, but significant within the roughness [13]. Salizzoni et al [31] determined that the shear stress is dependent on λp, whereas Marciotto and Fisch, who also studied 2D arrays [22], found it is not. Of the studies including aligned arrays some determined that shear stress is not dependent [10] on λp while others found it was [3].…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the role of the effect of turbulence generated locally and in the oncoming boundary layer upon the flow in the canyon and its ventilation characteristics remain unclear. Recently, Marciotto and Fisch [22] investigated a 2D canyon with varying AR = 4, 6, and 8 and, surprisingly, concluded that "the flow within the canyon is little sensitive to the turbulence level of the flow above" a statement which is claimed to be supported by Ricciardelli and Polimeno [28], but is contradicted by Salizzoni et al [31] who found that the structure of the external flow influences the structure of the cavity flow. Although Ricciardelli and Polimeno [28] noted that the mean and fluctuating characteristics of canyon flow are more dependent on local geometry than that of the oncoming flow, that observation was made on the basis of measurements within large obstacles in only two boundary layers, one with a smooth ground plane and one with very small roughness elements when compared with the measurement roughness obstacles.…”

Section: Introductionmentioning

confidence: 99%

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Effect of upstream flow regime on street canyon flow mean turbulence statistics

2014

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Section: Spatially Averaged Turbulence Statisticsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of upstream flow regime on street canyon flow mean turbulence statistics

2014

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“…The canopy energy budget in urban areas is a whole subject in urban climate studies and can vary significantly from one neighborhood to another, also influencing atmospheric dispersion [16,17]. The canopy energy budget is strongly affected by the aspect-ratio either because it changes the local radiation absorption by the street and walls or because it impacts the wind circulation [18,19]. It is worth mentioning that the canopy energy budget drives the diurnal cycle of the boundary layer process by altering momentum and heat exchanges between atmosphere above and the surface layer [20].…”

Section: Introductionmentioning

confidence: 99%

Implementation of Observed Sky-View Factor in a Mesoscale Model for Sensitivity Studies of the Urban Meteorology

et al. 2018

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Abstract:The sky view factor (SVF) is an important radiometric parameter for assessing the canopy energy budget of urban areas. There are several methods to determine the SVF observationally. The most common is taking a photo with a digital camera equipped with a fish-eye lens and then converting ratio of sky area to canopy area into SVF. However, most urban canopy models use this variable as derived from idealized canopy geometry. To evaluate the effect of inputting observed SVFs in numerical models, we evaluated a mesoscale model's performance in reproducing surface wind and surface temperature when subjected to different ways of SVF prescription. The studied area was the Metropolitan Area of São Paulo (MASP) in Brazil. Observed SVFs were obtained for 37 sites scattered all over the MASP. Three simulations, A, B, and C, with different SVF and aspect-ratio prescriptions, were performed to analyze the effect of SVF on the urban canopy parameterization: Simulation A (standard) used the original formulation of the Town Energy Budget (TEB) model, computing the SVFs from the aspect-ratios; Simulation B used the observed SVFs, but keeps aspect-ratios as original; and Simulation C used the aspect-ratios computed from observed SVFs. The results show that in general inputting observed SVFs improves the model capability of reproducing temperature at surface level. The comparison of model outputs with data of regular meteorological stations shows that the inclusion of observed values of SVFs enhances model performance, reducing the RMSE index by up to 3 • C. In this case, the model is able to better reproduce the expected effects in the wind field, and consequently the temperature advection, of the urban boundary layer to a large urban area. The result of Simulation C shows that the surface wind and temperature intensity for all urban types is higher than those of Simulation A, because of the lower values of the aspect ratio. The urban type with high density of tall buildings increase up to 1 m s −1 in the wind speed, and approximately 1 • C in temperature, showing the importance of a better representation of the urban structure and the SVF database improvement.

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“…Esta altura será na superfície a partir de um determinado tamanho absoluto da cavidade (estimado na ordem de 10 0 ou 10 1 m). Essa hipótese é capaz de explicar as principais diferenças entre os experimentos físicos do túnel de vento e numérico obtidos pelo LES (Marciotto e Fisch, 2012).…”

Section: Resultsunclassified

Estudo do escoamento turbulento atmosférico utilizando ensaios em túnel de vento e simulação numérica

Schuch

Marciotto

Acevedo

et al. 2014

Rev. bras. meteorol.

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A estrutura do campo de vento e da turbulência atmosférica gerada no interior de uma cavidade rasa é analisada com o uso de ensaios realizados em túnel de vento e simulação numérica com um modelo bidimensional de grandes turbilhões (LES). As cavidades são maquetes estáticas, que podem representar regiões de pequenas clareiras na Amazônia ou de "canyons" urbanos representando a geometria de cidades modernas. Os resultados sugerem que, apesar das diferenças de escalas, a organização da turbulência nos dois experimentos contém similaridades em algumas regiões. Foi verificada a dependência que a intensidade da turbulência, o perfil do vento e termos do balanço de Energia Cinética Turbulenta têm com a velocidade do fluxo livre, com as dimensões (largura) da cavidade e com a posição relativa dentro da cavidade.

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Wind tunnel study of turbulent flow past an urban canyon model

Cited by 8 publications

References 21 publications

Effect of upstream flow regime on street canyon flow mean turbulence statistics

Effect of upstream flow regime on street canyon flow mean turbulence statistics

Implementation of Observed Sky-View Factor in a Mesoscale Model for Sensitivity Studies of the Urban Meteorology

Estudo do escoamento turbulento atmosférico utilizando ensaios em túnel de vento e simulação numérica

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