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On the inviscid instability of a circular jet with external flow

Published online by Cambridge University Press:  20 April 2006

Alfons Michalke  and
Gunter Hermann
Alfons Michalke
Affiliation:
Hermann-Föttinger-Institut für Thermo- und Fluiddynamik, Technische Universität Berlin, West Germany
Gunter Hermann
Affiliation:
Wien, Austria
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Abstract

The influence of an external flow velocity on the instability of a circular jet has been investigated by means of the inviscid linearized stability theory. The instability properties of spatially growing axisymmetric and first-order azimuthal disturbances show that the external flow inhibits the instability of the circular jet, but increases the unstable frequency range. Similarity considerations lead to the result that, in a first approximation, the disturbed flow field is independent of the external flow velocity, if the axial co-ordinate is contracted by a suitably chosen stretching factor and if the disturbance frequency is reduced by the same factor. It is concluded that the large-scale structure of jet turbulence is modified in the same manner by the external flow.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 114 , January 1982 , pp. 343 - 359
Copyright
© 1972 Cambridge University Press

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