Two-dimensional buoyant plumes in a uniform co-flow
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Publication Date
2021Journal Title
Journal of Fluid Mechanics
ISSN
0022-1120
Publisher
Cambridge University Press (CUP)
Volume
932
Number
ARTN A41
Pages
a41
Type
Article
This Version
AM
Metadata
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Hunt, G., & Webb, J. (2021). Two-dimensional buoyant plumes in a uniform co-flow. Journal of Fluid Mechanics, 932 (ARTN A41), a41. https://doi.org/10.1017/jfm.2021.1004
Abstract
<jats:p>The behaviour of turbulent, buoyant, planar plumes is fundamentally coupled to the environment within which they develop. The effect of a background stratification directly influences a plumes buoyancy and has been the subject of numerous studies. Conversely, the effect of an ambient co-flow, which directly influences the vertical momentum of a plume, has not previously been the subject of theoretical investigation. The governing conservation equations for the case of a uniform co-flow are derived and the local dynamical behaviour of the plume is shown to be characterised by the scaled source Richardson number and the relative magnitude of the co-flow and plume source velocities. For forced, pure and lazy plume release conditions the co-flow acts to narrow the plume and reduce both the dilution and the asymptotic Richardson number relative to the classic zero co-flow case. Analytical solutions are developed for pure plumes from line sources, and for highly forced and highly lazy releases from sources of finite width in a weak co-flow. Contrary to releases in quiescent surroundings, our solutions show that all classes of release can exhibit plume contraction and the associated necking. For entraining plumes, a dynamical invariance spatially only occurs for pure and forced releases and we derive the co-flow strengths that lead to this invariance.</jats:p>
Keywords
plumes, thermals
Sponsorship
Innovate UK (106163)
Identifiers
External DOI: https://doi.org/10.1017/jfm.2021.1004
This record's URL: https://www.repository.cam.ac.uk/handle/1810/332875
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International
Licence URL: https://creativecommons.org/licenses/by-nc-nd/4.0/
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