Entrainment by turbulent fountains

Burridge, H. C. ; Hunt, G. R. (2016-02-04)


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 ≤ Fr₀ ≤ 25) and thereby encompass the entrainment across all classes of fountain behaviour identified to date. We identify scalings for the entrained volume flux Qᴇ, in terms of Fr₀ and the source volume flux Q₀, 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 Fr₀ ≲ 0.1.