Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-08T07:27:12.514Z Has data issue: false hasContentIssue false

Spinning modes on axisymmetric jets. Part 1

Published online by Cambridge University Press:  20 April 2006

P. J. R. Strange
Affiliation:
Department of Applied Mathematical Studies, University of Leeds, Leeds LS2 9JT, England Present address: Noise Department, Rolls-Royce Ltd, P.O. Box 31, Derby DE2 8BJ.
D. G. Crighton
Affiliation:
Department of Applied Mathematical Studies, University of Leeds, Leeds LS2 9JT, England

Abstract

Linear instability analysis is applied to the slowly diverging mean profile of a turbulent axisymmetric jet and used to predict the transverse structure and axial evolution of large-scale wavelike modes with azimuthal wavenumber m = 1. Comparisons are made with measurements of filtered velocity fluctuations, and of pressure fluctuations, taken in a jet with coherent forcing at the exit plane, at Strouhal numbers St = fD/U0 around 0.5,f = ω/2π being the frequency, D the nozzle diameter and U0 the mean centreline exit velocity. The transverse structure at each axial station is well predicted by linear theory, as is the phase speed and its variation with axial distance. The downstream evolution of amplitude is much less well predicted, presumably because of cumulative nonlinear effects in the experiments, though the inclusion of mean-flow divergence itself constitutes a significant improvement over the theory for parallel flow, and in somecases permits calculation of the wave evolution well into the decay phase without any reference to viscous effects on the disturbance.

Type
Research Article
Copyright
© 1983 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. 1980 J. Fluid Mech. 98, 1.
Batchelor, G. K. & Gill, A. E 1962 J. Fluid Mech. 14, 529.
Bechert, D. W. & Pfizenmaier, E. 1975 J. Sound Vib. 43, 581.
Bechert, D. W. & Pfizenmaier, E. 1977 AIAA J. 15, 1268.
Chan, Y. Y. 1974 Phys. Fluids 17, 46.
Chan, Y. Y. 1977 AIAA J. 15, 992.
Crighton, D. G. & Gaster, M. 1976 J. Fluid Mech. 77, 397.
Crow, S. C. 1968 J. Fluid Mech. 33, 1.
Crow, S. C. & Champagne, F. H. 1971 J. Fluid Mech. 48, 547.
Ffowcs Williams, J. E. & Kempton, A. J. 1978 J. Fluid Mech. 84, 673.
Gotoh, K. 1968 J. Phys. Soc. Japan 24, 1137.
Grant, A. J. 1974 J. Fluid Mech. 66, 707.
Huerre, P. 1980 Phil. Trans. R. Soc. Lond. A293, 643.
Huerre, P. & Scott, J. F. 1980 Proc. R. Soc. Lond. A371, 509.
Ko, D. R. S., Kubota, T. & Lees, L. 1970 J. Fluid Mech. 40, 315.
Mankbadi, R. & Liu, J. T. C. 1981 Phil. Trans. R. Soc. Lond. A298, 541.
Mattingly, G. E. & Chang, C. C. 1974 J. Fluid Mech. 65, 541.
Michalke, A. 1971 Z. Flugwiss. 19, 319.
Moore, C. J. 1977 J. Fluid Mech. 80, 321.
Moore, C. J. 1978 In Structure and Mechanisms of Turbulence II (ed. H. Fiedler). Lecture Notes in Physics, vol. 76, p. 254. Springer.
Morfey, C. L. 1979 In Mechanics of Sound Generation in Flows (ed. E.-A. Müller), pp. 1218. Springer.
Orszag, S. A. & Crow, S. C. 1970 Stud. Appl. Maths 49, 167.
Plaschko, P. 1979 J. Fluid Mech. 92, 209.
Rienstra, S. W. 1983 J. Sound Vib. 86, 539.
Strange, P. J. R. 1981 Ph.D. thesis, University of Leeds.
Stuart, J. T. 1963 Hydrodynamic stability. In Laminar Boundary Layers (ed. L. Rosenhead), p. 492. Oxford University Press.