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Experiments in Fluids

, Volume 48, Issue 3, pp 409–420 | Cite as

Volumetric velocity measurements of vortex rings from inclined exits

  • Daniel R. TroolinEmail author
  • Ellen K. Longmire
Research Article

Abstract

Vortex rings were generated by driving pistons within circular cylinders of inner diameter D = 72.8 mm at a constant velocity U 0 over a distance L = D. The Reynolds number, U 0 L/(2ν), was 2500. The flow downstream of circular and inclined exits was examined using volumetric 3-component velocimetry (V3V). The circular exit yields a standard primary vortex ring that propagates downstream at a constant velocity and a lingering trailing ring of opposite sign associated with the stopping of the piston. By contrast, the inclined nozzle yields a much more complicated structure. The data suggest that a tilted primary vortex ring interacts with two trailing rings; one associated with the stopping of the piston, and the other associated with the asymmetry of the cylinder exit. The two trailing ring structures, which initially have circulation of opposite sign, intertwine and are distorted and drawn through the center of the primary ring. This behavior was observed for two inclination angles. Increased inclination was associated with stronger interactions between the primary and trailing vortices as well as earlier breakdown.

Keywords

Vortex Vorticity Particle Image Velocimetry Vortex Ring Vortical Structure 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Supplementary material

348_2009_745_MOESM1_ESM.wmv (219 kb)
Supplementary material 1 (WMV 219 kb)

Supplementary material 2 (WMV 287 kb)

Supplementary material 3 (WMV 380 kb)

Supplementary material 4 (WMV 291 kb)

Supplementary material 5 (WMV 366 kb)

References

  1. Allen JJ, Auvity B (2002) Interaction of a vortex ring with a piston vortex. J Fluid Mech 465:353–378zbMATHCrossRefMathSciNetGoogle Scholar
  2. Allen JJ, Chong MS (2000) Vortex formation in front of a piston moving through a cylinder. J Fluid Mech 416:1–28zbMATHCrossRefMathSciNetGoogle Scholar
  3. Cater JE, Soria J, Lim TT (2004) The interaction of the piston vortex with a piston-generated vortex ring. J Fluid Mech 499:327–343zbMATHCrossRefGoogle Scholar
  4. Dabiri JO, Colin SP, Costello JH, Gharib M (2005) Flow patterns generated by oblate medusan jellyfish: field measurements and laboratory analyses. J Exp Biol 208:1257–1265CrossRefGoogle Scholar
  5. Didden N (1979) On the formation of vortex rings: rolling-up and the production of circulation. J Appl Math Phys 30:101–116CrossRefGoogle Scholar
  6. Gharib M, Rambod E, Shariff K (1998) A universal time scale for vortex ring formation. J Fluid Mech 360:121–140zbMATHCrossRefMathSciNetGoogle Scholar
  7. Keane R, Adrian R (1990) Optimization of particle image velocimeters. Part 1: double pulsed systems. Meas Sci Tech 1:1202–1215CrossRefGoogle Scholar
  8. Krueger PS (2005) An over-pressure correction to the slug model for vortex ring circulation. J Fluid Mech 545:427–443zbMATHCrossRefGoogle Scholar
  9. Lim TT (1998) On the breakdown of vortex rings from inclined nozzles. Phys Fluids 10(7):1666–1671zbMATHCrossRefMathSciNetGoogle Scholar
  10. Lim TT, Nickels TB (1995) Vortex rings. In: Green SI (ed) Fluid vortices. Kluwer, DordrechtGoogle Scholar
  11. Ohmi K, Li HY (2000) Particle tracking velocimetry with new algorithms. Meas Sci Tech 11(6):603–616CrossRefGoogle Scholar
  12. Pereira F, Gharib M, Dabiri D, Modarress D (2000) Defocusing digital particle image velocimetry: a 3-component 3-dimensional DPIV measurement technique. Application to bubbly flows. Exp Fluids 29(suppl 1):S78–S84CrossRefGoogle Scholar
  13. Pereira F, Stuer H, Graff EC, Gharib M (2006) Two-frame 3D particle tracking. Meas Sci Tech 17:1680–1692CrossRefGoogle Scholar
  14. Shariff K, Leonard A (1992) Vortex rings. Annu Rev Fluid Mech 24:235–279CrossRefMathSciNetGoogle Scholar
  15. Webster DR, Longmire EK (1998) Vortex rings from cylinders with inclined exits. Phys Fluids 10(2):400–416CrossRefGoogle Scholar
  16. Zhou J, Adrian RJ, Balachandar S, Kendall TM (1999) Mechanisms for generating coherent packets of hairpin vortices in channel flow. J Fluid Mech 387:353–396zbMATHCrossRefMathSciNetGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Fluid Mechanics DivisionTSI IncorporatedSt. PaulUSA
  2. 2.Department of Aerospace Engineering & MechanicsUniversity of MinnesotaMinneapolisUSA

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