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Experiments in Fluids

, 22:447 | Cite as

On the evolution of laminar vortex rings

  • A. Weigand
  • M. Gharib
Article

Abstract

Using Laser Doppler Anemometry (LDA) and Digital Particle Image Velocimetry (DPIV), the physical properties of laminar vortex rings are investigated in the Reynolds-number range 830 ≤ Re ≤ 1650. The measured initial circulations of the vortex rings are found to agree well with corrected versions of the vorticity-flux (slug-flow) model proposed by Didden and Pullin. The DPIV and LDA data show excellent agreement regarding local velocities and vortex-ring circulations. The DPIV data depict the distribution of the vorticity and circulation in the core regions, where the resulting vorticity distributions are found to be self-similar Gaussian profiles. The propagation velocity of the vortex rings is well approximated by an analytical model of Saffman for large core sizes. In the asymptotic limit t → ∞, the trajectories are in excellent agreement with the exact Stokes-dipole solution of Cantwell and Rott.

Keywords

Vorticity Vortex Ring Laser Doppler Anemometry Digital Particle Image Velocimetry Vorticity Distribution 
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.

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Copyright information

© Springer-Verlag 1997

Authors and Affiliations

  • A. Weigand
    • 1
  • M. Gharib
    • 1
  1. 1.California Institute of TechnologyGraduate Aeronautical LaboratoriesUSA

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