On the robustness of emptying filling boxes to sudden changes in the wind
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Accepted version
Author(s)
Craske, J
Hughes, G
Type
Journal Article
Abstract
We determine the smallest instantaneous increase in the strength of an opposing windthat is necessary to permanently reverse the forward displacement flow that is drivenby a two-layer thermal stratification. With an interpretation in terms of the flow’s ener-getics, the results clarify why the ventilation of a confined space with a stably-stratifiedbuoyancy field is less susceptible to being permanently reversed by the wind than theventilation of a space with a uniform buoyancy field. For large opposing wind strengthswe derive analytical upper and lower bounds for the system’s marginal stability, which ex-hibit a good agreement with the exact solution, even for modest opposing wind strengths.The work extends a previous formulation of the problem (Lishman & Woods 2009,Build-ing and Env.44, pp. 666-673) by accounting for the transient dynamics and energeticsassociated with the homogenisation of the interior, which prove to play a significant rolein buffering temporal variations in the wind.
Date Issued
2019-06-10
Date Acceptance
2019-02-26
ISSN
0022-1120
Publisher
Cambridge University Press (CUP)
Journal / Book Title
Journal of Fluid Mechanics
Volume
868
Copyright Statement
© 2019 Cambridge University Press. This paper has been accepted for publication and will appear in a revised form, subsequent to peer-review and/or editorial input by Cambridge University Press.
Source Database
manual-entry
Subjects
Fluids & Plasmas
01 Mathematical Sciences
09 Engineering
Publication Status
Published
Date Publish Online
2019-04-11