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Entrainment by turbulent fountains

Published online by Cambridge University Press:  04 February 2016

H. C. Burridge
Affiliation:
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, UK
G. R. Hunt*
Affiliation:
Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
*
Email address for correspondence: [email protected]

Abstract

Experimental measurements of entrainment by turbulent fountains from circular sources in quiescent uniform environments are presented. Our results span almost four orders of magnitude in the source Froude number ($0.004\leqslant \mathit{Fr}_{0}\leqslant 25$) and thereby encompass the entrainment across all classes of fountain behaviour identified to date. We identify scalings for the entrained volume flux $Q_{E}$, in terms of $\mathit{Fr}_{0}$ and the source volume flux $Q_{0}$, within a number of distinct Froude-number bands corresponding to each class of fountain. Additionally we identify a distinct class of new behaviour, as yet unreported, for $\mathit{Fr}_{0}\lesssim 0.1$.

Type
Papers
Copyright
© 2016 Cambridge University Press 

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