Wind tunnel experiment on high-buoyancy gas dispersion around isolated cubic building

Lin, Chao; Ooka, Ryozo; Kikumoto, Hideki; Sato, Taiki; Arai, Masato

doi:10.1016/j.jweia.2020.104226

Cited by 17 publications

(5 citation statements)

References 27 publications

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“…As σc could not express the relative instability of concentration for different cases, concentration fluctuation intensity was adopted, normalizing the standard deviation of concentration by mean concentration (Lin et al, 2020). It expresses the relative instability of the concentration and is defined as 𝐼 𝑐 = 𝜎 𝑐 /〈𝑐〉.…”

Section: Velocity and Concentration Fluctuationsmentioning

confidence: 99%

Boundary layer wind tunnel modeling experiments on pumping ventilation through a three-story reduce-scaled building with two openings

Zhong

Lin

Sun

et al. 2021

Building and Environment

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Section: Velocity and Concentration Fluctuationsmentioning

confidence: 99%

Boundary layer wind tunnel modeling experiments on pumping ventilation through a three-story reduce-scaled building with two openings

Zhong

Lin

Sun

et al. 2021

Building and Environment

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“…There has been some initial research into the effect of buoyancy released into the near wake of a floor-mounted cube (e.g. Lin, Ooka, Kikumoto, Sato, & Arai, 2020; Olvera, Choudhuri, & Li, 2008; Tominaga & Stathopoulos, 2018). Those authors have investigated the effect of pollutant source location and the effect of additional cubes up- and downstream.…”

Section: Introductionmentioning

confidence: 99%

The influence of buoyancy upon pollution trapping and dispersal in the wake of a backward-facing step

Charlwood

Frank

Wykes

2023

Flow

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The importance of buoyancy relative to free-stream flow is described using an adapted Froude number $Fr' = U/f_0^{1/3}$ , where $U$ is the flow speed and $f_0$ is the exhaust buoyancy flux per unit length. We varied $Fr'$ by changing the free-stream flow rate, the exhaust flow rate and the buoyancy of the exhaust. We have experimentally identified two flow regimes, depending on the value of $Fr'$ . For high $Fr'$ (low buoyancy), dispersion is driven by inertial forces in the wake and the amount of a pollutant in the wake is independent of $Fr'$ . For moderate $Fr'$ , a wall plume develops up the back of the step, directly feeding the pollutant into the shear layer, but without altering the shape of the wake. This wall plume reduces the amount of pollutant trapped behind the step. We developed an analytic model to describe the quantity of pollutant trapped behind the step. The model predicts the transition from buoyancy being negligible to being the dominant transport mechanism within the wake. We have hypothesised and observed some evidence of a third regime at low $Fr'$ , when the buoyancy is sufficient to distort the macrostructure of the shear layer and wake.

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“…Therefore, many wind tunnel experiments and computational fluid dynamics (CFD) simulations of gas dispersion around isolated buildings have been performed. Researchers have studied the flow and gas dispersion around lowrise buildings [7][8][9][10][11][12][13][14][15][16][17][18] and high-rise buildings [19][20][21] with gas discharge holes located on the ground [14,[18][19][20][21], in the top area of the building [7][8][9][10][11]13,15,17], in the lateral surface of the building [15], or in the air ahead or behind of the building [12,13,16]. CFD models include steady or unsteady Reynolds-averaged Navier-Stokes (RANS) models [7][8][9]11,13,14,[17][18][19][20], large-eddy simulation (LES) models [7,9,10,12,…”

Section: Introductionmentioning

confidence: 99%

Turbulence and Pollutant Statistics around a High-Rise Building with and without Overhangs

Jiang,

Wu,

2023

Atmosphere

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Wind flow around an isolated building is highly turbulent. Facade appurtenances can further increase the complexity of the flow, which strongly affects the gas dispersion around the building. This study investigated the turbulence and pollutant statistics around a high-rise building with large-eddy simulations and determined the influence of overhangs on the local wind flow and dispersion. Large-scale periodic vortex motion was detected. The results indicated that both the oncoming flow and the flow around the building followed a standard Gaussian distribution, whereas the occurrence frequencies of pollutant concentrations were far from Gaussian for pollutants discharged from both the rooftop and the ground behind the building. Near the pollutant sources, the positive concentration fluctuations occurred more frequently; occasionally, positive and negative fluctuations occurred equally. For the majority of areas far from the source, negative fluctuations were more common, but the maximum positive fluctuations were much larger. Overhangs changed the local flow structures near the building facade. Both the maximum concentration fluctuation and the maximum occurrence frequency decreased in the region between overhangs because turbulence was restricted.

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Wind tunnel experiment on high-buoyancy gas dispersion around isolated cubic building

Cited by 17 publications

References 27 publications

Boundary layer wind tunnel modeling experiments on pumping ventilation through a three-story reduce-scaled building with two openings

Boundary layer wind tunnel modeling experiments on pumping ventilation through a three-story reduce-scaled building with two openings

The influence of buoyancy upon pollution trapping and dispersal in the wake of a backward-facing step

Turbulence and Pollutant Statistics around a High-Rise Building with and without Overhangs

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