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The Stability of Swirling Jets

Published online by Cambridge University Press:  25 April 2016

Colin S. Coleman*
Affiliation:
Department of Mathematics, Monash University, Clayton 3168, Victoria

Abstract

The stability of a swirling cylindrical jet of compressible fluid is examined by performing a normal mode analysis and numerically solving the eigenvalue problem. Perturbations of the form f(r)exp[i(ωt-mϕ-kz)] are considered, where f is any fluid variable. Instabilities which are characteristic of both a non-swirling (top-hat) jet and a Rankine vortex are investigated for a particular axial wavenumber.

The vortex instabilities are weak, and are found to remain weak when axial flow is present. The jet instabilities are much stronger, but axial flow is a stabilizing influence. The positive helicity (km > 0) non-axisymmetric modes (m ≠ 0) are stabilized by a small component of azimuthal flow. The axisymmetric mode (m = 0) and the negative helicity non-axisymmetric modes persist in rapidly swirling jets, but with a greatly reduced growth rate.

Type
Theoretical
Copyright
Copyright © Astronomical Society of Australia 1989

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References

Broadbent, E. G. 1984, Proc. R. Soc. Lond. A., 392, 279.Google Scholar
Broadbent, E. G. & Moore, D. W. 1979, Phil. Trans. R. Soc. Lond. A., 290, 353.Google Scholar
Ferrari, A., Trussoni, E. & Zaninetti, L. 1978, Astron. Astrophys., 64, 43.Google Scholar
Gill, A. E. 1965, Phys. Fluids, 8, 1428.CrossRefGoogle Scholar
Hardee, P. E. 1979, Astrophys. J., 234, 47.CrossRefGoogle Scholar
Hardee, P. E. 1982, Astrophys. J., 261, 457.Google Scholar
Sozou, C. 1986, Proc. R. Soc. Lond. A., 405, 289.Google Scholar
Sozou, C. 1987a, Proc. R. Soc. Lond. A., 411, 207.Google Scholar
Sozou, C. 1987b, Proc. R. Soc. Lond. A., 413, 225.Google Scholar