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Active control of a round jet using two unsteady microjets

  • Hong Kong Polytechnic University
  • University Town of Shenzhen

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Unsteady microjets are used to control the mixing performance of a round jet at a Reynolds number of 8000. Two microjets were placed at diametrically opposite locations upstream of the nozzle exit. We explored the effects of the mass rate ratio Cm and forcing frequency ratio fex/f0 of the microjets on the primary jet, where fex is the microjet forcing frequency and f0 the predominant vortex frequency in the free jet. The Cm and fex/f0 examined are 0 ∼ 15.4% and 0 ∼ 1.28, respectively. The flow was measured using hot wire, flow visualization and particle imaging velocity techniques in two orthogonal planes through the jet axis. The jet centreline decay rate exhibits a strong dependence on fex /f0. Given fex /f0 ≈ 1.0, this decay rate displays three types of distinct behaviours for Cm investigated in terms of the response of large-scale coherent structures to the control, which is different from previous studies. The flow physics and control mechanisms are explored.

Original languageEnglish
Title of host publicationProceedings of the 18th Australasian Fluid Mechanics Conference, AFMC 2012
EditorsP.A. Brandner, B.W. Pearce
PublisherAustralasian Fluid Mechanics Society
ISBN (Electronic)9780646583730
StatePublished - 2012
Externally publishedYes
Event18th Australasian Fluid Mechanics Conference, AFMC 2012 - Launceston, Australia
Duration: 3 Dec 20127 Dec 2012

Publication series

NameProceedings of the 18th Australasian Fluid Mechanics Conference, AFMC 2012

Conference

Conference18th Australasian Fluid Mechanics Conference, AFMC 2012
Country/TerritoryAustralia
CityLaunceston
Period3/12/127/12/12

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