Paper 3: Volume 4 No.1 June 2005 Edition
Unsteady Flow Reversal in a Natural
Ventilation Stack
- Model Scale Tests
L. Claesson1 and D. W. Etheridge2
1 Department of Technology and the Built
Environment, University of Gävle, Sweden
2 School of the Built Environment, University of Nottingham, UK
Abstract
Measurements of the unsteady flow in a ventilation stack
of a school have been made at model scale in an environmental wind tunnel.
The results confirm the expectation that the stack is well-sited, in that
it was difficult to induce flow reversal except over a narrow range of
wind directions and the amount of reversal was small (reversal percentage
< 5 %). The results also show that the technique is capable of reliably
detecting such small reversal percentages.
Key words: wind driven ventilation, stack
ventilation, stack flows, flow reversal, scale model tests, wind tunnel
tests.
References
Blomsterberg Å, Wahlström Å and Sandberg M: (2002) IEA
Pilot Study Report.
Chiu Y-H and Etheridge DW: (2004) “Experimental technique
to determine unsteady flow in natural ventilation stacks at model scale”
Jnl Wind Eng & Ind Aerod, 92,
pp291-313.
Etheridge
DW: (2000) “Unsteady flow effects due to fluctuating wind pressures in
natural ventilation design - instantaneous flow rates” Building and Environment, 35, (4), pp321-337.
Etheridge
DW: (2002) “Nondimensional methods for natural ventilation design”. Building
and Environment, 37, pp1057-1072.
Wiren BG: (1985)
“Effects of surrounding buildings on wind pressure distributions, Part
1”. National Swedish
Institute for Building Research, Report M85-19,
Gävle
,
Sweden
.
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