Journal of Fluid Mechanics



Observations on transition in plane bubble plumes


M.  Alam a1 and V. H.  Arakeri a1
a1 Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560 012, India

Article author query
alam m   [Google Scholar] 
arakeri vh   [Google Scholar] 
 

Abstract

Flow visualization studies of plane laminar bubble plumes have been conducted to yield quantitative data on transition height, wavelength and wave velocity of the most unstable disturbance leading to transition. These are believed to be the first results of this kind. Most earlier studies are restricted to turbulent bubble plumes. In the present study, the bubble plumes were generated by electrolysis of water and hence very fine control over bubble size distribution and gas flow rate was possible to enable studies with laminar bubble plumes. Present observations show that (a) the dominant mode of instability in plane bubble plumes is the sinuous mode, (b) transition height and wavelength are related linearly with the proportionality constant being about 4, (c) wave velocity is about 40% of the mean plume velocity, and (d) normalized transition height data correlate very well with a source Grashof number. Some agreement and some differences in transition characteristics of bubble plumes have been observed compared to those for similar single-phase flows.

(Published Online April 26 2006)
(Received January 31 1992)
(Revised March 24 1993)



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