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An experimental investigation of the composition of jet noise

Published online by Cambridge University Press:  29 March 2006

G. Krishnappa  and
G. T. Csanady
G. Krishnappa
Affiliation:
University of Waterloo, Ontario Present address: National Research Council, Ottawa, Ontario.
G. T. Csanady
Affiliation:
University of Waterloo, Ontario
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Abstract

Noise intensity measurements per octave band have been carried out in the far field of a small circular nozzle, at angles 0-150° from the jet axis, with and without vortex generators. The results, interpreted in the light of recent theoretical conclusions, confirm Lighthill's original suggestion that the dominant noise radiator is the pressure-shear x-r quadrupole at all but the lowest frequencies. At very low frequencies Reynolds stress-shear x-x and x-r quadrupoles contribute comparable amounts of radiation. When the product of Strouhal number (based on nozzle diameter and jet velocity) and jet Mach number exceeds unity the geometrical acoustics approximation becomes valid, but even at such high frequencies the shear noise contribution dominates. Vortex generators, while reducing noise intensity, do not appear to modify drastically the above composition of noise radiators.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 37 , Issue 1 , 5 June 1969 , pp. 149 - 159
Copyright
© 1969 Cambridge University Press

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References

Csanady, G. T. 1966 The effect of mean velocity variations on jet noise. J. Fluid Mech. 26, 183–97.Google Scholar
Ffowcs WILLIAMS, J. E. 1960 Some thoughts on the effect of aircraft motion and eddy convection on the noise from air jets. University of Southampton, Aero. Astr. Rep. no. 155.Google Scholar
Howes, W. L. 1960 Similarity of the far noise field of jets. NASA TR no. R-52.Google Scholar
Jones, I. S. F. 1968 Aerodynamic noise dependent on mean shear. J. Fluid Mech. 33, 65–72.Google Scholar
Krishnappa, G. 1967 Some studies on jet noise. Ph.D. thesis, University of Waterloo.
Lighthill, M. J. 1952 On sound generated aerodynamically I. Proc. Roy. Soc. A 211, 564–87.Google Scholar
Lighthill, M. J. 1954 On sound generated aerodynamically II. Proc. Roy. Soc. A 222, 1–32.Google Scholar
Mollö-christensen, E., KOLPIN, M. A. & MARTUCCELLI, J. R. 1964 Experiments on jet flows and jet noise, far field spectra and directivity patterns. J. Fluid Mech. 18, 285–301.Google Scholar
Proudman, I. 1953 The generation of noise by isotropic turbulence. Proc. Roy. Soc. A 214, 119–32.Google Scholar
Ribner, H. S. 1958 Note on acoustic energy flow in a moving medium. UTIAS TN no. 4.Google Scholar
Smith, H. R. & WANG, H. T. 1946 Contracting cones giving uniform throat speeds. J. Aero Sci. pp. 356–60.Google Scholar