A round turbulent jet produced by an oscillating diaphragm

R. D. James, Jeffrey W Jacobs, A. Glezer

Research output: Contribution to journalArticle

79 Citations (Scopus)

Abstract

A round turbulent water jet produced normal to, and at the center of a submerged, resonantly driven diaphragm is investigated experimentally. The jet which is formed without mass injection and is comprised entirely of radially entrained fluid, is present only when the excitation amplitude exceeds a given threshold. Above this excitation level, a small cluster of cavitation bubbles appears near the center of the diaphragm. The bubbles grow, apparently collapse, and then disappear during each oscillation cycle. It is conjectured that the jet is synthesized by time-periodic coalescence of vortex rings that are produced by secondary flow around the bubbles or by the collapse of the bubbles. It is remarkable that even though the jet results from a strong time-periodic excitation and its time-periodic features are detected throughout the present range of measurements, the time-averaged jet structure is similar to that of a conventional turbulent round jet in that the increase in its width and in the inverse of its centerline velocity are both linear functions of the distance from the actuator. In contrast to conventional jets, the present synthetic jets can be manipulated on relatively short time scales that are comparable to the excitation period.

Original languageEnglish (US)
Pages (from-to)2484-2495
Number of pages12
JournalPhysics of Fluids
Volume8
Issue number9
StatePublished - Sep 1996

Fingerprint

turbulent jets
diaphragms
Diaphragms
bubbles
excitation
hydraulic jets
vortex rings
secondary flow
cavitation flow
Secondary flow
coalescing
Bubbles (in fluids)
Coalescence
Cavitation
actuators
Vortex flow
injection
Actuators
oscillations
cycles

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Computational Mechanics
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Condensed Matter Physics

Cite this

A round turbulent jet produced by an oscillating diaphragm. / James, R. D.; Jacobs, Jeffrey W; Glezer, A.

In: Physics of Fluids, Vol. 8, No. 9, 09.1996, p. 2484-2495.

Research output: Contribution to journalArticle

James, RD, Jacobs, JW & Glezer, A 1996, 'A round turbulent jet produced by an oscillating diaphragm', Physics of Fluids, vol. 8, no. 9, pp. 2484-2495.
James, R. D. ; Jacobs, Jeffrey W ; Glezer, A. / A round turbulent jet produced by an oscillating diaphragm. In: Physics of Fluids. 1996 ; Vol. 8, No. 9. pp. 2484-2495.
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