Influence of thermal stability on the ventilation of a 3-D building array
Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review
Author(s)
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Detail(s)
Original language | English |
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Article number | 106969 |
Journal / Publication | Building and Environment |
Volume | 183 |
Online published | 14 Jun 2020 |
Publication status | Published - Oct 2020 |
Link(s)
Abstract
The influence of thermal stability on the ventilation of a cubic building array is examined via large-eddy simulation. For unstable stratification (with bulk Richardson numbers in the range −0.5≲Rb < 0), ventilation timescales decrease as the ground-level heating increases; in particular, the mean tracer age and pollutant retention timescale scale linearly with the mean circulation timescale. For stable stratification (0 < Rb≲0.3), however, the ventilation timescales increase with stronger ground-level cooling even though the mean stream-wise wind speed and turbulence kinetic energy remain approximately constant. The ventilation pathway changes for stable stratification because pollutants preferentially escape through the lateral openings rather than the roof level. It is argued that conventional time-averaged turbulence statistics (e.g. Reynolds stresses) provide an incomplete picture of the ventilation mechanism under stable stratification.
Research Area(s)
- Flow regime, Pollutant dispersion, Stable stratification, Tracer age, Urban boundary layer
Citation Format(s)
Influence of thermal stability on the ventilation of a 3-D building array. / Duan, G.; Ngan, K.
In: Building and Environment, Vol. 183, 106969, 10.2020.
In: Building and Environment, Vol. 183, 106969, 10.2020.
Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review