A ‘turbulent spot’ in an axisymmetric free shear layer. Part 1

M. Sokolov, Fazle Hussain, S. J. Kleis, Z. D. Husain

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


A three-dimensional 'turbulent spot' has been induced in the axisymmetric free mixing layer of a 12. 7 cm diameter air jet by a spark generated at the nozzle boundary layer upstream of the exit. The spot coherent-structure signature, buried in the large-amplitude random fluctuating signal, has been educed at three downstream stations within the apparent self-preserving region of the mixing layer at the jet exit speed of 20 m s** minus **1. The eduction has been performed through digital phase averaging of the spot signature from 200 realizations. The mixing-layer spot is a large-scale elongated structure spanning the entire width of the layer but does not appear to exhibit a self-similar shape. The dynamics of the mixing-layer spot and its eduction are more complicated than those of the boundary-layer spot. This paper discusses the data acquisition and processing techniques and the results based on the streamwise velocity signals. Refs.

Original languageEnglish (US)
Pages (from-to)65-95
Number of pages31
JournalJournal of Fluid Mechanics
Issue number1
StatePublished - Jan 1 1980

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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