Experiments in Fluids

, Volume 12, Issue 3, pp 189–199

Flow visualization of interactions among large coherent structures in an axisymmetric jet

  • C. O. Paschereit
  • D. Oster
  • T. A. Long
  • H. E. Fiedler
  • I. Wygnanski
Originals

DOI: 10.1007/BF00188258

Cite this article as:
Paschereit, C.O., Oster, D., Long, T.A. et al. Experiments in Fluids (1992) 12: 189. doi:10.1007/BF00188258

Abstract

Interactions between large coherent structures are visualized with both schlieren photography in two air jets and dye photography in a water jet. The density difference needed for the schlieren technique is provided by an electrically heated wire ring surrounding the jet. External forcing with either single axisymmetric, single non-symmetric, combined axisymmetric or combined non-symmetric modes was applied. It was found that forcing the jet with a pair of different spinning modes leads to azimuthal distortions of the mean flow. This observation confirms and explains existing hotwire data. Simultaneous excitation with two axisymmetric modes may produce structures of higher modes or even cause structurally undistinguishable development. Streamwise structures are observed both in the unforced jet and in the axisymmetrically forced jet. They do not seem to be caused by a Görtier instability from the concave curvature of the conventional nozzle, since they were also found in a jet flow from a specially designed nozzle with only convex contraction surface.

Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • C. O. Paschereit
    • 1
  • D. Oster
    • 1
  • T. A. Long
    • 1
  • H. E. Fiedler
    • 1
  • I. Wygnanski
    • 1
  1. 1.Aerospace and Mechanical Engineering DepartmentUniversity of ArizonaTucsonUSA
  2. 2.Hermann-Föttinger-Institut für Thermo- und Fluiddynamik, Technische Universität BerlinBerlinGermany
  3. 3.Israel Aircraft IndustriesBen Gurion AirportIsrael

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