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Experimental study on the flow and noise characteristics of underexpanded notched slot jets

Published online by Cambridge University Press:  04 July 2016

S. B. Verma  and
E. Rathakrishnan
S. B. Verma
Affiliation:
Department of Aerospace Engineering, Indian Institute of Technology Kanpur, India
E. Rathakrishnan
Affiliation:
Department of Aerospace Engineering, Indian Institute of Technology Kanpur, India
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Abstract

An experimental investigation has been carried out to study the effect of notches on the flow and noise characteristics of 2:1 elliptic-slot jets. The effect of variation in notch geometry is also investigated. The presence of the notch is found to provide low-velocity regions in the notched-minor-axis plane thereby intensifying the jet growth along that plane. The interaction of these low-velocity regions with the mean flow results in shorter core-lengths. At under-expansion, the shock-cell lengths are weakened considerably in notched jets resulting in significant reductions in the overall jet noise level. Azimuthal directivity of elliptic jets indicate higher noise intensity radiated along major-axis ends relative to minor-axis sides. Notches seem to circumferentially modify the noise emission characteristics and significantly bring down the noise levels along major-axis-unnotched plane. Polar directivity indicates reduction in both shock noise and jet mixing noise in the forward quadrant.

Type
Research Article
Information
The Aeronautical Journal , Volume 105 , Issue 1047 , April 2001 , pp. 267 - 276
Copyright
Copyright © Royal Aeronautical Society 2002 

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