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Effect of a sharp edge on an excited jet

Published online by Cambridge University Press:  20 April 2006

N. W. M. Ko
Affiliation:
Engineering Department, University of Cambridge

Abstract

An experimental study of an excited jet interrupted normally by a 90° sharp edge is described in this paper. Based on schlieren technique, it is possible to distinguish three flow regions: the main jet flow, the wake flow behind the sharp edge and the redirected flow on the surface. By following the individual articially excited jet vortices, it is possible to observe the structure and to estimate the convection velocity of these vortices in the three flow regions. By comparison with the results of the uninterrupted jet, the effect of the sharp edge is obtained and presented.

Type
Research Article
Copyright
© 1981 Cambridge University Press

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References

Arctander, C. L., Hodge, C. G. & Tate, R. B. 1975 Development of noise-reduction concepts for 727 and 737 airplanes. J. Acoust. Soc. Am. 58, 155172.Google Scholar
Arndt, R. E. A., Fuchs, H. V. & Michel, U. 1978 Laboratory study of jet-noise suppressors. J. Acoust. Soc. Am. 63, 10601068.Google Scholar
Arndt, R. E. A., Tran, N. C. & Barefoot, G. 1974 Turbulence and acoustic characteristics of screen perturbed jets. A.I.A.A. J. 12, 261262.Google Scholar
Batchelor, G. K. 1967 An Introduction to Fluid Dynamics. Cambridge University Press.
Bauer, A. B. 1961 Vortex shedding from thin flat plates parallel to the free stream. J. Aerospace Sci. 28, 340341.Google Scholar
Chan, Y. Y. 1974 Spatial waves in turbulent jets. Phys. Fluids 17, 4653.Google Scholar
Crow, S. C. & Champagne, F. H. 1971 Orderly structure in jet turbulence. J. Fluid Mech. 48, 547591.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, 337367.Google Scholar
Davis, S. S. 1975 Theory of discrete vortex noise. A.I.A.A. J. 13, 375380.Google Scholar
Donaldson, C. D. & Snedeker, R. S. 1971 A study of free jet impingement. Part 1. Mean properties of free and impinging jets. J. Fluid Mech. 45, 281319.Google Scholar
Donaldson, C. D., Snedeker, R. S. & Margolis, D. P. 1971 A study of free jet impingement. Part 2. Free jet turbulent structure and impingement heat transfer. J. Fluid Mech. 45, 477512.Google Scholar
Frasca, R. L. 1975 Noise-reduction programs for DC-8 and DC-9 airplanes. J. Acoust. Soc. Am. 58, 173191.Google Scholar
Fuchs, H. V. & Michel, U. 1977 Experimental evidence of turbulence source coherence effecting jet noise. A.I.A.A. Paper no. 77–1348.Google Scholar
Heavens, S. N. 1978 Visualization of unsteady jets and aerodynamic noise fields. 13th Int. Cong. on High Speed Photography and Photonics, paper TS14-2, 86. Tokyo.Google Scholar
Heavens, S. N. 1980 Visualization of the acoustic excitation of a subsonic jet. J. Fluid Mech. 100, 185192.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, 4978.Google Scholar
Ko, N. W. M. & Davies, P. O. A. L. 1975 Some covariance measurements in a subsonic jet. J. Sound Vib. 41, 347358.Google Scholar
Kwan, A. S. H. & Ko, N. W. M. 1977 Covariance measurements in subsonic coaxial jets. J. Sound Vib. 52, 567578.Google Scholar
Lau, J. C., Fisher, M. J. & Fuchs, H. V. 1972 The instrinsic structure of turbulent jets. J. Sound Vib. 22, 379406.Google Scholar
Moore, C. J. 1977 The role of shear-layer instability waves in jet exhaust noise. J. Fluid Mech. 80, 321367.Google Scholar
Rockwell, D. O. & Niccolls, W. O. 1972 Natural breakdown of planar jets. Trans. A.S.M.E. D, J. Basic Engng 94, 720730.Google Scholar
Roshko, A. 1976 Structure of turbulent shear flows: a new look. A.I.A.A. J. 14, 13491357.Google Scholar
Scharton, T. D. & White, P. H. 1972 Simple pressure source model of jet noise. J. Acoust. Soc. Am. 52, 399412.Google Scholar
Sforza, P. M., Stasi, W., Pazienza, J. & Smorto, M. 1978 Flow measurements in leading-edge vortices. A.I.A.A. J. 16, 218224.Google Scholar
Tam, C. K. W. 1974 Discrete tones of isolated airfoils. J. Acoust. Soc. Am. 55, 11731177.Google Scholar
Townsend, A. A. 1956 The Structure of Turbulent Shear Flow. Cambridge University Press.