Turbulence suppression in free shear flows by controlled excitation

K. B.M.Q. Zaman, Fazle Hussain

Research output: Contribution to journalArticlepeer-review

207 Scopus citations

Abstract

In an attempt to explain the mechanics of turbulence suppression previously observed in jets under controlled excitation, the near fields of four circular jets, a plane jet and a plane mixing layer, all with laminar efflux boundary layers, have been explored through hot-wire measurements. It is shown that controlled excitation, induced acoustically as well as by vibrating ribbons, can reduce turbulence intensities in all these flows. Reduction by as much as 80% is observed, the maximum decrease occurring at about 400 theta //e downstream from the exit; theta //e is the initial shear-layer momentum thickness. The flow-fields with and without excitation for a typical case of turbulence suppression have been studied in detail. The suppression effect is apparently a consequence of earlier transition of the shear layer vortices. Refs.

Original languageEnglish (US)
Pages (from-to)133-159
Number of pages27
JournalJournal of Fluid Mechanics
Volume103
DOIs
StatePublished - Jan 1 1981

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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