Abstract
Multigrid cross-correlation digital particle image velocimetry (MCCDPIV) is used to investigate the stability and structure of low Reynolds number axisymmetric jets. The in-plane velocities, out-of-plane vorticity and some of the components of the Reynolds stress tensor are measured. Two Reynolds numbers based on the orifice outlet diameter are examined (680 and 1,030) at two different positions: one close to the orifice, ranging from 2D 0 to 5D 0 (D 0 is the orifice diameter); and the other further from the orifice, ranging from 10D 0 to 14.4D 0. The results show that the lower Reynolds number jet (Re=680) is marginally unstable in the near-orifice region and is best described as laminar. Further downstream some intermittent structures are observed in the jet, and the growth in integrated turbulent kinetic energy with axial position indicates that the jet is also unstable in this region. For the higher Reynolds number jet (Re=1,030) the increasing size and intensity of vortical structures in the jet in the near-orifice region observed from the MCCDPIV data and the growth in integrated turbulent kinetic energy indicate that the jet is unstable. Further downstream this jet is best described as transitional or turbulent. From flow visualisation images in the near-orifice region it seems that, for both Reynolds numbers, shear layer roll-up occurs when the jet exits the orifice and enters the quiescent fluid in the tank, resulting in vortical structures that appear to grow as the jet proceeds. This is indicative of instability in both cases and is consistent with previous flow visualisation studies of low Reynolds number round jets. Discrepancies observed between the flow visualisation results and the MCCDPIV data is addressed. On the basis of flow visualisation results it is generally assumed that round jets are unstable at very low Reynolds number, however the present work shows that this assertion may be incorrect.
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References
Andrade EN, Tsien LC (1937) The velocity distribution in a liquid into liquid jet. Proc Phys Soc Lond 49:381–391
Batchelor GK, Gill AE (1962) Analysis of the instability of axisymmetric jets. J Fluid Mech 14:529–551
Cater JE, Soria J (2002) The evolution of round zero-net-mass-flux jets. J Fluid Mech 472:167–200
Cohen J, Wygnanski I (1987) The evolution of instabilities in the axisymmetric jet. Part 1. The linear growth of disturbances near the nozzle. J Fluid Mech 176:191–219
Crow SC, Champagne FH (1971) Orderly structure in jet turbulence. J Fluid Mech 43:547–591
Danaila I, Duśek J, Anselmet F (1997) Coherent structures in a round, spatially evolving, unforced, homogeneous jet at low Reynolds numbers. Phys Fluids 9:3323–3342
Fouras A, Soria J (1998) Accuracy of out-of-plane velocity measurements derived from in-plane velocity fields. Exp Fluids 25:409–430
Gursul I, Lusseyran D, Rockwell D (1990) On interpretation of flow visualisation of unsteady shear flows. Exp Fluids 9:257–266
Gutmark E, Ho CM (1983) Preferred modes and the spreading rates of jets. Phys Fluids 26:2932–2938
Hama FR (1962) Streaklines in a perturbed shear flow. Phys Fluids 5:644–650
Hussein HJ, Capp SP, George WK (1994) Velocity measurements in a high-Reynolds-number, momentum-conserving, axisymmetric, turbulent jet. J Fluid Mech 258:31–75
Ho C-M, Huerre P (1984) Perturbed free shear layers. Ann Rev Fluid Mech 16:365–424
Mattingly GE, Chang CC (1974) Unstable waves on an axisymmetric jet column. J Fluid Mech 65:541–561
Michalke A (1972) The instability of free shear layers. Prog Aerospace Sci 12:213–239
Michalke A (1984) Survey on jet instability theory. Prog Aerospace Sci 21:159–199
Mollendorf JC, Gebhart B (1973) An experimental and numerical study of the viscous stability of a round laminar vertical jet with and without thermal buoyancy for symmetric and asymmetric disturbances. J Fluid Mech 61:367–399
Panchapakesan NR, Lumley JL (1993) Turbulence measurements in axisymmetric jets of air and helium. Part 1. Air jet. J Fluid Mech 246:197–223
Petersen RA, Samet MM (1988) On the preferred mode of jet instability. J Fluid Mech 194:153–173
Rankin GW, Sridhar K, Arulraja M, Kumar KR (1983) An experimental investigation of laminar axisymmetric submerged jets. J Fluid Mech 133:217–231
Reynolds AJ (1962) Observations of a liquid-into-liquid jet. J Fluid Mech 14:552–556
Soria J (1998) Multigrid approach to cross-correlation digital PIV and HPIV analysis. In: Thomson MC, Hourigan K (eds) Proceedings of the 13th Australasian Fluid Mechanics Conference, Monash University, Melbourne, pp 381–384
Tennekes H, Lumley JL (1974) A first course in turbulence, 3rd edn. The MIT Press, Cambridge, MA
Viilu A (1962) An experimental determination of the minimum Reynolds number for instability in a free jet. J Appl Mech 29:506
Weisgraber TH, Liepmann D (1998) Turbulent structure during transition to self-similarity in a round jet. Exp Fluids 24:210–224
Willert CE, Gharib M (1991) Digital particle image velocimetry. Exp Fluids 10:181–193
Yoda M, Hesselink L, Mungal MG (1994) Instantaneous three-dimensional concentration measurements in the self-similar region of a round high-Schmidt-number jet. J Fluid Mech 279:313–350
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O’Neill, P., Soria, J. & Honnery, D. The stability of low Reynolds number round jets. Exp Fluids 36, 473–483 (2004). https://doi.org/10.1007/s00348-003-0751-5
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DOI: https://doi.org/10.1007/s00348-003-0751-5