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Vortex induction and mass entrainment in a small-aspect-ratio elliptic jet

Published online by Cambridge University Press:  21 April 2006

Chih-Ming Ho  and
Ephraim Gutmark
Chih-Ming Ho
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089, USA
Ephraim Gutmark
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089, USA
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Abstract

A passive technique of increasing entrainment was found by using a small-aspect-ratio elliptic jet. The entrainment ratio of an elliptic jet was several times greater than that of a circular jet or a plane jet. The self-induction of the asymmetric coherent structure caused azimuthal distortions which were responsible for engulfing large amounts of surrounding fluid into the jet. In an elliptic jet, an interesting feature in the initial stability process is that the thickness of the shear layer varies around the nozzle. The data indicated that instability frequency was scaled with the thinnest initial momentum thickness which was associated with the maximum vorticity. Turbulence properties were also examined and were found to be significantly different in the major- and minor-axis planes.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 179 , June 1987 , pp. 383 - 405
Copyright
© 1987 Cambridge University Press

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