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Aspect ratio effect on elliptical sonic jet mixing

Published online by Cambridge University Press:  07 June 2016

V. Chauhan ,
S.M. Aravindh Kumar  and
E. Rathakrishnan
V. Chauhan*
Affiliation:
Department of Aerospace Engineering, Indian Institute of Technology, Kanpur, India
S.M. Aravindh Kumar*
Affiliation:
Department of Aerospace Engineering, Indian Institute of Technology, Kanpur, India
E. Rathakrishnan*
Affiliation:
Department of Aerospace Engineering, Indian Institute of Technology, Kanpur, India
*
vinayc@iitk.ac.in
aravinds@iitk.ac.in
erath@iitk.ac.in
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Abstract

The effects of aspect ratio on elliptical sonic jet decay at different levels of under-expansion has been studied experimentally. Elliptical sonic jets from orifices of same area with aspect ratios (AR) 2, 4 and 6 at nozzle pressure ratios 2 to 5 in steps of 1 have also been studied. A circular jet from an orifice with an area equal to that of elliptical orifice was also studied for comparison. Jet centreline pressure decay, spread and waves present in the jet core were analysed. The results show that the mixing of the elliptical jet is superior to the circular jet, at all the nozzle pressure ratios of the present study. Also, the aspect ratio of the elliptical orifice has a strong influence on the jet mixing. Elliptical jets of aspect ratio 4 and 6 experience a significantly higher mixing than the aspect ratio 2 jet, till the under-expansion level corresponding to Mach disk formation. For higher under-expansion levels, the mixing of AR 4 and 6 jets become inferior to that of the AR 2 jet.

Keywords

elliptical jetaxis-switchingcore lengthunder-expansionshock cell
Type
Research Article
Information
The Aeronautical Journal , Volume 120 , Issue 1230 , August 2016 , pp. 1197 - 1214
Copyright
Copyright © Royal Aeronautical Society 2016 

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