Hostname: page-component-78c5997874-j824f Total loading time: 0 Render date: 2024-11-02T21:43:24.740Z Has data issue: false hasContentIssue false
  • English
  • Français

Instability waves in twin supersonic jets

Published online by Cambridge University Press:  26 April 2006

Philip J. Morris
Philip J. Morris
Affiliation:
Department of Aerospace Engineering, Penn State University, University Park, PA 16802, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

Calculations are presented for the characteristics of instability waves in the initial mixing region of twin circular supersonic jets. Two models for the basic jet flow are used. In the first, the jets are modelled as two circular vortex sheets. In the second, realistic velocity and density profiles are used. It is shown that the unsteady flow fields of the two jets interact before the time-averaged jets flows have merged. The normal modes or instability waves are classified by their symmetry properties in the twin-jet case and their asymptotic behaviour for large jet separations. Calculations of the growth rates and phase velocities are made for these modes as a function of jet separation and mixing-layer thickness. The associated pressure distributions are also presented. In the realistic jet profile calculations the effect of jet separation is found to be relatively weak. For modes that are even about the symmetry plane between the two jets the pressure levels are found to increase near this plane as the jet separation decreases.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 220 , November 1990 , pp. 293 - 307
Copyright
© 1990 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Gaster, M., Kit, E. & Wygnanski, I., 1985 Large scale structures in a forced turbulent mixing layer. J. Fluid Mech. 150, 23–39.Google Scholar
Morris, P. J.: 1988 A note on the effect of forward flight on shock spacing in circular jets. J. Sound Vib. 121, 175–177.Google Scholar
Morris, P. J., Bhat, T. R. S. & Chen, G. 1989 A linear shock cell model for jets of arbitrary exit geometry. J. Sound Vib. 132, 199–211.Google Scholar
Petersen, R. A. & Samet, M., 1988 On the preferred mode of jet instability. J. Fluid Mech. 194, 153–173.Google Scholar
Powell, A.: 1953 On the noise emanating from a two-dimensional jet above the critical pressure. Aero. Q. 4, 103–122.Google Scholar
Sedel'Nikov, T. K.: 1967 The dispersion relations for multilayer jets and for several jets. In Physics of Aerodynamic Noise (ed. A. V. Rimskiy-Korsakov). Moscow: Nauka. (Transl. NASA TTF-538, 1969.)
Seiner, J. M., Manning, J. C. & Ponton, M. K., 1988 Dynamic pressure loads associated with twin supersonic plume resonance. AIAA J. 26, 954–960.Google Scholar
Tam, C. K. W.: 1986 On the screech tones of supersonic rectangular jets. AIAA Paper 86–1866.Google Scholar
Tam, C. K. W.: 1987 Stochastic model theory of broadband shock associated noise from supersonic jets. J. Sound Vib. 116, 265–302.Google Scholar
Tam, C. K. W. & Burton, D. E. 1984a Sound generated by instability waves of supersonic flows. Part 1. Two-dimensional mixing layers. J. Fluid Mech. 138, 249–271.Google Scholar
Tam, C. K. W. & Burton, D. E. 1984b Sound generated by instability waves of supersonic flows. Part 2. Axisymmetric jets. J. Fluid Mech. 138, 273–295.Google Scholar
Tam, C. K. W. & Morris, P. J. 1980 The radiation of sound by the instability waves of a compressible plane turbulent shear layer. J. Fluid Mech. 98, 349–381.Google Scholar
Tam, C. K. W. & Seiner, J. M. 1987 Analysis of twin supersonic plume resonance. AIAA Paper 87–2695.Google Scholar
Tam, C. K. W., Seiner, J. M. & Yu, J. C., 1986 Proposed relationship between broadband shock associated noise and screech tones. J. Sound Vib. 110, 309–321.Google Scholar
Tam, C. K. W. & Tanna, H. K. 1982 Shock associated noise of supersonic jets from convergent–divergent nozzles. J. Sound Vib. 81, 337–358.Google Scholar
Tranter, C. J.: 1968 Bessel Functions with Some Physical Applications, Sec. 2.6. English Universities Press.
Wlezian, R. W.: 1987 Nozzle geometry effects on supersonic jet interaction. AIAA Paper 87–2694.Google Scholar