The preferred mode of incompressible jets: Linear frequency response analysis

X. Garnaud, L. Lesshafft, P. J. Schmid, P. Huerre

Research output: Contribution to journalArticlepeer-review

142 Scopus citations

Abstract

The linear amplification of axisymmetric external forcing in incompressible jet flows is investigated within a fully non-parallel framework. Experimental and numerical studies have shown that isothermal jets preferably amplify external perturbations for Strouhal numbers in the range 0. 25 ≤ St D ≤ 0. 5, depending on the operating conditions. In the present study, the optimal forcing of an incompressible jet is computed as a function of the excitation frequency. This analysis characterizes the preferred amplification as a pseudo-resonance with a dominant Strouhal number of around 0. 45. The flow response at this frequency takes the form of a vortical wavepacket that peaks inside the potential core. Its global structure is characterized by the cooperation of local shear-layer and jet-column modes. © 2013 Cambridge University Press.
Original languageEnglish (US)
Pages (from-to)189-202
Number of pages14
JournalJournal of Fluid Mechanics
Volume716
DOIs
StatePublished - Jan 1 2013
Externally publishedYes

Bibliographical note

Generated from Scopus record by KAUST IRTS on 2022-09-13

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Condensed Matter Physics

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