Instabilities and drop formation in cylindrical liquid jets in reduced gravity

Edwards, A. P. R., Osborne, B. P., Stoltzfus, J. M., Howes, T. and Steinberg, T. A. (2002) Instabilities and drop formation in cylindrical liquid jets in reduced gravity. Physics of Fluids, 14 10: 3432-3438. doi:10.1063/1.1501825

Author Edwards, A. P. R.
Osborne, B. P.
Stoltzfus, J. M.
Howes, T.
Steinberg, T. A.
Title Instabilities and drop formation in cylindrical liquid jets in reduced gravity
Journal name Physics of Fluids   Check publisher's open access policy
ISSN 1070-6631
Publication date 2002
Sub-type Article (original research)
DOI 10.1063/1.1501825
Volume 14
Issue 10
Start page 3432
End page 3438
Total pages 7
Place of publication USA
Publisher American Institute of Physics
Collection year 2002
Language eng
Subject C1
671199 Transport equipment not elsewhere classified
240502 Fluid Physics
Abstract The effects of convective and absolute instabilities on the formation of drops formed from cylindrical liquid jets of glycerol/water issuing into still air were investigated. Medium-duration reduced gravity tests were conducted aboard NASA's KC-135 and compared to similar tests performed under normal gravity conditions to aid in understanding the drop formation process. In reduced gravity, the Rayleigh-Chandrasekhar Equation was found to accurately predict the transition between a region of absolute and convective instability as defined by a critical Weber number. Observations of the physics of the jet, its breakup, and subsequent drop dynamics under both gravity conditions and the effects of the two instabilities on these processes are presented. All the normal gravity liquid jets investigated, in regions of convective or absolute instability, were subject to significant stretching effects, which affected the subsequent drop and associated geometry and dynamics. These effects were not displayed in reduced gravity and, therefore, the liquid jets would form drops which took longer to form (reduction in drop frequency), larger in size, and more spherical (surface tension effects). Most observed changes, in regions of either absolute or convective instabilities, were due to a reduction in the buoyancy force and an increased importance of the surface tension force acting on the liquid contained in the jet or formed drop. Reduced gravity environments allow better investigations to be performed into the physics of liquid jets, subsequently formed drops, and the effects of instabilities on these systems. In reduced gravity, drops form up to three times more slowly and as a consequence are up to three times larger in volume in the theoretical absolute instability region than in the theoretical convective instability region. This difference was not seen in the corresponding normal gravity tests due to the masking effects of gravity. A drop is shown to be able to form and detach in a region of absolute instability, and spanning the critical Weber number (from a region of convective to absolute instability) resulted in a marked change in dynamics and geometry of the liquid jet and detaching drops. (C) 2002 American Institute of Physics.
Keyword Mechanics
Physics, Fluids & Plasmas
Absolute Instability
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Chemical Engineering Publications
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Citation counts: TR Web of Science Citation Count  Cited 6 times in Thomson Reuters Web of Science Article | Citations
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Created: Tue, 14 Aug 2007, 18:12:37 EST