Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-28T06:24:17.492Z Has data issue: false hasContentIssue false
  • English
  • Français

The role of shear-layer instability waves in jet exhaust noise

Published online by Cambridge University Press:  11 April 2006

C. J. Moore
C. J. Moore
Affiliation:
Advanced Research Laboratories, Rolls-Royce Limited, P.O. Box 31, Derby, England
Get access Rights & Permissions [Opens in a new window]

Abstract

Large-scale structures in the form of instability waves are an inherent part of a shearlayer mixing process. Such structures are shown to be present in an acoustically and aerodynamically well behaved jet even at high Mach numbers. They do not directly radiate significant acoustic power in a subsonic jet, but do govern the production of the turbulent fluctuations which radiate broad-band jet noise. Over the whole subsonic Mach number range, a significant increase in jet noise can be produced by exciting the shear layer with a fluctuating pressure at the nozzle of only 0·08 % of the jet dynamic head but with the correct Strouhal number. Such excitation by internal acoustic, aerodynamic or thermal fluctuations could explain the variability of jet noise measurements between different rigs and could also be responsible for some components of ‘excess’ noise.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 80 , Issue 2 , 25 April 1977 , pp. 321 - 367
Copyright
© 1977 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

Acton, E. 1976 Modelling of large eddies in a two-dimensional shear layer. J. Fluid Mech. 76, 561–592.Google Scholar
Ahuja, K. K. 1972 An experimental study of subsonic jet noise with particular reference to the effects of upstream disturbance. M.Phil. thesis, Q.M.C. London University.
Ahuja, K. K. 1973 Correlation and prediction of jet noise. J. Sound Vib. 29, 155–168.Google Scholar
Arndt, R. E. A. & George, W. K. 1974 Investigation of large scale coherent structure in a jet and its relevance to jet noise. N.A.S.A. Contractor Rep. no. 138908.Google Scholar
Bechert, D. & Pfizenmaier, E. 1975a On the amplification of broadband jet noise by pure tone excitation. J. Sound Vib. 43, 581–587.Google Scholar
Bechert, D. & Pfizenmaier, E. 1975b On wavelike perturbations in a free jet travelling faster than the mean flow in the jet. J. Fluid Mech. 72, 341–352.Google Scholar
Bishop, K. A., Ffowcs Williams, J. E. & Smith, W. 1971 On noise sources of the unsuppressed high speed jet. J. Fluid Mech. 50, 21–30.Google Scholar
Bradshaw, P., Ferriss, D. M. & Johnson, R. F. 1964 Turbulence in the noise producing region of a circular jet. J. Fluid Mech. 19, 591–624.Google Scholar
Brown, G. L. & Roshko, A. 1974 On density effects and large-scale structures in turbulent mixing layers. J. Fluid Mech. 64, 775–816.Google Scholar
Bushell, K. W. 1971 A survey of low velocity and coaxial jet noise with application to prediction. J. Sound Vib. 17, 271–282.Google Scholar
Chan, Y. Y. 1974a Spatial waves in turbulent jets. Phys. Fluids 17, 46–53.Google Scholar
Chan, Y. Y. 1974b Spatial waves in turbulent jets. Part II. Phys. Fluids 17, 1667–1670.Google Scholar
Chan, Y. Y. 1975 Non-linear spatial wave development in an axisymmetric turbulent jet. NRL Aero. Rep. no. 14756, LR 585.Google Scholar
Chan, Y. Y. & Templin, J. T. 1975 Suppression of spatial waves by distortion of jet velocity profile. Phys. Fluids 17, 2124–25.Google Scholar
Crighton, D. G. 1975 Basic principles of aerodynamic noise generation. Prog. Aerospace Sci. 16, 31–96.Google Scholar
Crighton, D. G. & Gaster, M. 1976 Instability of slowly diverging jet flow. J. Fluid Mech. 77, 397–413.Google Scholar
Crow, S. C. 1972 Acoustic gain of a turbulent jet. Meeting Div. Fluid Dyn. Am. Phys. Soc. Univ. Colorado, paper IEG.
Crow, S. C. & Champagne, F. H. 1971 Orderly structure in jet turbulence. J. Fluid Mech. 48, 547–91.Google Scholar
Davies, P. O. A. L., Fisher, M. J. & Barratt, M. J. 1963 The characteristics of turbulence in the mixing region of a round jet. J. Fluid Mech. 15, 337–367.Google Scholar
Fisher, M. J., Lush, P. A. & Harper-Bourne, M. 1973 Jet noise. J. Sound Vib. 28, 563–585.Google Scholar
Fuchs, H. U. 1972a Measurement of pressure fluctuations within subsonic turbulent jets. J. Sound Vib. 22, 361–378.Google Scholar
Fuchs, H. U. 1972b Correlations of the fluctuating pressure in subsonic turbulent jets. J. Sound Vib. 23, 72–99.Google Scholar
Grant, A. J. 1974 A numerical model of instability in axisymmetric jets. J. Fluid Mech. 66, 707–724.Google Scholar
Grosche, F. R. 1972 Investigation of the sound source distribution in turbulent gas flow. Trans. DGLR Dtsche Gesellschafte für Luft- und Raumfahrt E. V., Berlin no. 6850.Google Scholar
Hardin, J. C. 1973 Analysis of noise produced by an orderly structure of turbulent jets. N.A.S.A. Tech. Note, D 7242.
Hoch, R. G., Duponchel, J. P., Cocking, B. J. & Bryce, W. C. 1972 Studies of the influence of density on jet noise. 1st Int. Symp. Air Breathing Engines, Marseille.
Jones, B. G. & Planchon, H. P. 1971 A study of the local pressure field in turbulent shear flow and its relation to aerodynamic noise generation. N.A.S.A. Contractor Rep. no. 134493.Google Scholar
Ko, N. W. M. & Davies, P. O. A. L. 1971 The near field within the potential cone of subsonic cold jets. J. Fluid Mech. 50, 49–78.Google Scholar
Lau, J. C. 1971 Ph.D. thesis, Southampton University.
Lighthill, M. J. 1952 On sound generated aerodynamically. I. General theory. Proc. Roy. Soc. A 211, 564–587.Google Scholar
Lighthill, M. J. 1954 On sound generated aerodynamically. II. Turbulence as a sound source. Proc. Roy. Soc. A 222, 1–32.Google Scholar
Lighthill, M. J. 1961 Sound generated aerodynamically. Bakerian Lecture. Proc. Roy. Soc. A 267, 147–182.Google Scholar
Lighthill, M. J. 1963 Jet noise. A.I.A.A. J. 1, 1587–1617.Google Scholar
Liu, C. H. & Maestrello, L. 1975 Propagation of sound through a real jet flow field. A.I.A.A. J. 13, 66–70.Google Scholar
Liu, J. T. C. 1974 Developing large-scale wavelike eddies and the near jet noise field. J. Fluid Mech. 62, 437–464.Google Scholar
Lush, P. A. 1971 Measurement of subsonic jet noise and comparison with theory. J. Fluid Mech. 46, 477–500.Google Scholar
Mclaughlin, D. K., Morrison, G. L. & Troutt, T. R. 1975 Experiments on the instability waves in a supersonic jet and their acoustic radiation. J. Fluid Mech. 69, 73–95.Google Scholar
Mattingly, G. E. & Chang, C. C. 1974 Unstable waves on an axisymmetric jet column. J. Fluid Mech. 65, 541–560.Google Scholar
Michalke, A. 1971a Instabilität eines kompressibelen runden Freistrahls unter Berüsichtigung des Einflusses der Strahlgrenzschichtdicke. Z. Flugwiss. 19, 319–328.Google Scholar
Michalke, A. 1971b New aspects of sound generation by circular jets. Fluid Dynamic Trans. 6, 439–448.Google Scholar
Michalke, A. 1972 An expansion scheme for the noise from circular jets. Z. Flugwiss. 20, 229–237.Google Scholar
Moore, D. W. & Saffman, P. G. 1975 The density of organized vortices in a turbulent mixing layer. J. Fluid Mech. 69, 465–473.Google Scholar
Morfey, C. L. 1970 Theory of sound generation in ducted compressible flows. with application to turbomachinery. Ph.D. thesis, University of Southampton.
Morris, P. J. 1971 The structure of turbulent shear flow. Ph.D. thesis, University of Southampton.
Petersen, R. A., Kaplan, R. E. & Laufer, J. 1974 Ordered structure and jet noise. N.A.S.A. Contractor Rep. no. 134733.Google Scholar
Pfizenmaier, E. 1973 On the instability of a sound influenced free jet. E.S.R.O. Tech. Trans. no. 122. (Translation of DFVLR Berlin Rep. DLR-FB 73–69.)Google Scholar
Scharton, T. D. & White, P. H. 1972 Simple pressure source model of jet noise. J. Acoust. Soc. Am. 52, 399–412.Google Scholar
Schubert, L. K. 1972 Numerical study of sound refraction by a jet flow. J. Acoust. Soc. Am. 51, 439–462.Google Scholar
Smart, A. E. & Moore, C. J. 1976 Aero engine applications of laser anemometry. A.I.A.A. J. 14, 363–370.Google Scholar
Vlasov, Ye. U. & Ginevskiy, A. S. 1974 Generation and suppression of turbulence in an axisymmetric turbulent jet in the presence of an acoustic influence. N.A.S.A. Tech. Trans. F 15721.
Winant, C. D. & Browand, F. K. 1974 Vortex pairing: the mechanism of turbulent mixing layer growth at moderate Reynolds numbers. J. Fluid Mech. 63, 237–255.Google Scholar
Wooldridge, C. E., Wooten, D. C. & Amaro, A. J. 1971 The structure of jet turbulence producing noise. N.A.S.A. Contractor Rep. no. 126483.Google Scholar