Numerical Study on Supersonic Co-flowing Jet with Varying Lip …
349
(Fig. 5d) shows that weak oblique shocks that emerge out crossover as Mach disk
and then reflects as expansion wave again reflects as shock wave and the process
continuous till the supersonic jets becomes subsonic. The secondary jet has weak
shocks (weaker than primary jet), and the shock crossover turns toward the jet axis.
Thus by increasing the LT, the core of the supersonic jet is reduced. This reduction in
the supersonic core signifies the mixing enhancement between primary and secondary
jet.
4 Conclusion
The jet mixing characteristics of supersonic jet surrounded by a supersonic co-flowing
jet with lip thickness of 2 mm and 7.75 mm are studied for the NPR 3 and 5 using
ANSYS CFX. Increase in LT and NPR results in reduction in the supersonic core
length. From the centerline pitot pressure plot, supersonic core length reduces by
18% for NPR 3, when LT increases from 2 mm to 7.75 mm, whereas the supersonic
core length reduces up to 65% for NPR 5. Pressure drop has been observed in the
total pressure contour because of the shock crossover. Subsonic pockets are visible
in Mach number contour. In turbulence contour, the core has reduced turbulence.
References
1. Sathish Kumar K, Chidambaram S (2019) Supersonic jet flow control using semi-circular
corrugated tabs. Aircraft Engineering and Aerospace Technology
2. Debiasi M, Papamoschou D (2001) Noise from imperfectly expanded supersonic coaxial jets.
AIAA 39:388–395
3. Murakami E, Papamoschou D (1986) Mixing layer characteristics of coaxial supersonic jets.
AIAA Paper, 86–0162
4. Sukumar VN, Sundaravadivelu T, Lovaraju P et al (2007) Effect of co-flow on near field
shock structure of under expanded central jet. In: Ninth Asian symposium on visualization.
ASV0031-001, Hong Kong, 4–9 June 2007
5. Sharma H, Vashishtha A, Rathakrishnan E et al (2008) Experimental study of overexpanded
co-flowing jets. Aeronaut J 112:537–546
6. De Satyajit, Rathakrishnan E et al (2018) Experimental study of supersonic co-flowing jet.
IMechE 2018
7. Naren Shankar R, Thanigaiarasu S, Rathakrishnan E (2016) Numerical characterization of lip
thickness on subsonic and correctly expanded sonic co-flowing jets. Trans Japan Soc Aeronaut
Space Sci 59(3):134–141. https://doi.org/10.2322/tjsass.59.134
8. Naren Shankar R (2017) Effect of lip thickness and bypass co-flowing jets. Ph. D. thesis, Anna
University
9. Naren Shankar R et al (2018) Co-flowing jet control using lip thickness variation. Int J Turbo
Jet Engines. https://doi.org/10.1515/tjj-2018-0024
10. Thanigaiarasu S, Naren Shankar R, Rathakrishnan E (2018) Influence of bypass ratio on
subsonic and correctly expanded sonic co-flowing jets with finite lip thickness. Proc Institut
Mech Eng Part G J Aerospace Eng 233(7):2536–2548. https://doi.org/10.1177/095441001878
2511
349
(Fig. 5d) shows that weak oblique shocks that emerge out crossover as Mach disk
and then reflects as expansion wave again reflects as shock wave and the process
continuous till the supersonic jets becomes subsonic. The secondary jet has weak
shocks (weaker than primary jet), and the shock crossover turns toward the jet axis.
Thus by increasing the LT, the core of the supersonic jet is reduced. This reduction in
the supersonic core signifies the mixing enhancement between primary and secondary
jet.
4 Conclusion
The jet mixing characteristics of supersonic jet surrounded by a supersonic co-flowing
jet with lip thickness of 2 mm and 7.75 mm are studied for the NPR 3 and 5 using
ANSYS CFX. Increase in LT and NPR results in reduction in the supersonic core
length. From the centerline pitot pressure plot, supersonic core length reduces by
18% for NPR 3, when LT increases from 2 mm to 7.75 mm, whereas the supersonic
core length reduces up to 65% for NPR 5. Pressure drop has been observed in the
total pressure contour because of the shock crossover. Subsonic pockets are visible
in Mach number contour. In turbulence contour, the core has reduced turbulence.
References
1. Sathish Kumar K, Chidambaram S (2019) Supersonic jet flow control using semi-circular
corrugated tabs. Aircraft Engineering and Aerospace Technology
2. Debiasi M, Papamoschou D (2001) Noise from imperfectly expanded supersonic coaxial jets.
AIAA 39:388–395
3. Murakami E, Papamoschou D (1986) Mixing layer characteristics of coaxial supersonic jets.
AIAA Paper, 86–0162
4. Sukumar VN, Sundaravadivelu T, Lovaraju P et al (2007) Effect of co-flow on near field
shock structure of under expanded central jet. In: Ninth Asian symposium on visualization.
ASV0031-001, Hong Kong, 4–9 June 2007
5. Sharma H, Vashishtha A, Rathakrishnan E et al (2008) Experimental study of overexpanded
co-flowing jets. Aeronaut J 112:537–546
6. De Satyajit, Rathakrishnan E et al (2018) Experimental study of supersonic co-flowing jet.
IMechE 2018
7. Naren Shankar R, Thanigaiarasu S, Rathakrishnan E (2016) Numerical characterization of lip
thickness on subsonic and correctly expanded sonic co-flowing jets. Trans Japan Soc Aeronaut
Space Sci 59(3):134–141. https://doi.org/10.2322/tjsass.59.134
8. Naren Shankar R (2017) Effect of lip thickness and bypass co-flowing jets. Ph. D. thesis, Anna
University
9. Naren Shankar R et al (2018) Co-flowing jet control using lip thickness variation. Int J Turbo
Jet Engines. https://doi.org/10.1515/tjj-2018-0024
10. Thanigaiarasu S, Naren Shankar R, Rathakrishnan E (2018) Influence of bypass ratio on
subsonic and correctly expanded sonic co-flowing jets with finite lip thickness. Proc Institut
Mech Eng Part G J Aerospace Eng 233(7):2536–2548. https://doi.org/10.1177/095441001878
2511