Large-scale instability of a fine-grained turbulent jet

Kangping Chen, D. G. Crighton

Research output: Contribution to journalArticle

Abstract

The initial growth of a large scale perturbation on a fine-grained turbulent jet is studied via linear stability analysis. The turbulent jet is assumed to be homogeneous and isotropic with zero mean shear, and the inviscid stream outside the jet has a uniform velocity profile. The incremental Reynolds stress caused by the large scale perturbation is modeled by a viscoelastic constitutive equation, following the analysis of Crow (1968). It is found that the jet is always unstable to both sinuous and varicose types of perturbation, with the sinuous mode having a larger growth rate. In particular, short waves are always amplified, in contrast to the short wave stabilization at low speed found by Townsend (1966) for a purely elastic jet. The growth rates of these short waves are finite, and are smaller than those for the classical Kelvin-Helmholtz instability of an inviscid jet, but larger than those for the Hooper-Boyd (1983) instability of a viscous jet with continuous velocity profile.

Original languageEnglish (US)
Pages (from-to)13-34
Number of pages22
JournalEuropean Journal of Mechanics, B/Fluids
Volume18
Issue number1
StatePublished - Jan 1 1999

ASJC Scopus subject areas

  • Mathematical Physics
  • Physics and Astronomy(all)

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