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Vortex structure and dynamics in the near field of a coaxial jet

Published online by Cambridge University Press:  26 April 2006

WERNER J. A. Dahm ,
Clifford E. Frieler  and
Grétar Tryggvason
WERNER J. A. Dahm
Affiliation:
Department of Aerospace Engineering, The University of Michigan, Ann Arbor, MI 48109-2140, USA
Clifford E. Frieler
Affiliation:
Graduate Aeronautical Laboratories, California Institute of Technology, Pasadena, CA 91125, USA
Grétar Tryggvason
Affiliation:
Department of Mechanical Engineering & Applied Mechanics, The University of Michigan, Ann Arbor, MI 48109-2125, USA
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Abstract

We present results from an experimental and numerical investigation into the structure of vortex patterns and the dynamics of their interactions for the incompressible flow in the near field of a round coaxial jet issuing into a quiescent ambient fluid. A two-colour planar laser-induced-fluorescence technique is used to document the flow field via still photographs and ciné sequences over a limited range of parameters. We examine the effects of varying the velocity ratio as well as the absolute velocities of the two coaxial streams for equal densities and for a single area ratio. Results show that a variety of widely differing near-field vortex patterns can arise, with very different interaction dynamics, which can depend both on the velocity ratio and on the absolute velocities of the two streams. The observed vortex structures and their dynamics are interpreted in terms of the instability of the initially cylindrical and concentric vorticity layers separating each of the fluid streams, and their subsequent rollup to form wake-like or shear-layer-like vortices. Our results show that in addition to the velocity jump across each of these vorticity layers, an accounting of the layer thicknesses and the wake defect within each layer can be essential to understanding the resulting near-field structure that occurs. Ensuing dynamical interactions between the vortices formed from each layer can produce a strong coupling between the development of the two layers. These resulting vortex structures and interaction dynamics are also seen to produce widely differing mixing patterns in the jet near field.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 241 , August 1992 , pp. 371 - 402
Copyright
© 1992 Cambridge University Press

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References

Balsa, T. F. & Gliebe P. R. 1977 Aerodynamics and noise of coaxial jets. AIAA J. 15, 1550–1558.Google Scholar
Beavers, G. S. & Wilson T. A. 1970 Vortex growth in jets. J. Fluid Mech. 44, 97–112.Google Scholar
Becker, H. A. & Massaro T. A. 1968 Vortex evolution in a round jet. J. Fluid Mech. 31, 435–448.Google Scholar
Champagne, F. H. & Wygnanski I. J. 1971 An experimental investigation of coaxial turbulent jets. Intl J. Heat Mass Transfer 14, 1445–1464.Google Scholar
Chan, W. T. & Ko N. M. W. 1978 Coherent structures in the outer mixing region of annular jets. J. Fluid Mech. 89, 515–533.Google Scholar
Chigier, N. A. & Beer J. M. 1964 The flow region near the nozzle in double concentric jets. Trans. ASME D: J. Basic Engng 86, 797–804.Google Scholar
Crow, S. C. & Champagne, F. H. 1971 Orderly structure in jet turbulence. J. Fluid Mech. 48, 547–591.
Dimotakis P. E. 1984 Two-dimensional shear layer entrainment AIAA J. 24, 1791–1796.Google Scholar
Dosanjh D. S., Yu, J. C. & Abdelhamid A. N. 1971 Reduction of noise from supersonic jet flows AIAA J. 9, 2346–2353.Google Scholar
Howe M. S. 1975 Contributions to the theory of aerodynamic noise, with application to excess jet noise and the theory of the flute J. Fluid Mech. 71, 625–673.Google Scholar
Ko, N. M. W. & Chan W. T. 1978 Similarity in the initial region of annular jets: three configurations. J. Fluid Mech. 84, 641–656.Google Scholar
Ko, N. M. W. & Chan W. T. 1979 The inner region of annular jets. J. Fluid Mech. 93, 549–584.Google Scholar
Ko, N. W. M. & Kwan A. S. H. 1976 The initial region of subsonic coaxial jets. J. Fluid Mech. 73, 305–332.Google Scholar
Koochesfahani, M. M. & Frieler C. E. 1989 Instability of nonuniform density free shear layers with a wake profile. AIAA J. 27, 1735–1740.Google Scholar
Kwan, A. S. H. & Ko N. W. M. 1977 The initial region of subsonic coaxial jets. Part 2. J. Fluid Mech. 82, 273–287.Google Scholar
Lighthill M. J. 1952 On sound generated aerodynamically. I. General theory Proc. R. Soc. Lond. A 211, 564–587.Google Scholar
Lighthill M. J. 1954 On sound generated aerodynamically. II. Turbulence as a source of sound Proc. R. Soc. Lond. A 222, 1–32.Google Scholar
Lighthill M. J. 1963 Jet noise. AIAA J. 1, 1507–1517.Google Scholar
Mattingly, G. E. & Criminale W. O. 1972 The stability of an incompressible two-dimensional wake. J. Fluid Mech. 51, 233–272.Google Scholar
Michalke A. 1964 On the inviscid instability of the hyperbolic-tangent velocity profile. J. Fluid Mech. 19, 543–556.Google Scholar
Michalke, A. & Hermann G. 1982 On the inviscid instability of a circular jet with external flow. J. Fluid Mech. 114, 343–359.Google Scholar
Miksad R. W. 1972 Experiments on the nonlinear stages of free-shear-layer transition. J. Fluid Mech. 56, 695–719.Google Scholar
MoUhring W. 1978 On vortex sound at low Mach number. J. Fluid Mech. 85, 685–691.Google Scholar
Olsen, W. A. & Friedman R. 1974 Jet noise from coaxial nozzles over a wide range of geometric and flow parameters. AIAA Paper 74–43.Google Scholar
Oster, D. & Wygnanski I. 1982 The forced mixing layer between parallel streams. J. Fluid Mech. 123, 91–130.Google Scholar
Powell A. 1964 Theory of vortex sound. J. Acoust. Soc. Am. 36, 177–195.Google Scholar
Ribeiro, M. M. & Whitelaw J. H. 1980 Coaxial jets with and without swirl. J. Fluid Mech. 96, 769–795.Google Scholar
Tanna, H. K. & Dean P. D. 1975 The effect of temperature on shock-free supersonic jet noise. J. Sound Vib. 39, 429–460.Google Scholar
White F. M. 1974 Viscous Fluid Flow. McGraw-Hill.
Williams T. J., Ali, M. R. M. H. & Anderson J. S. 1969 Noise and flow characteristics of coaxial jets. J. Mech. Engng Sci. 2, 133–141.Google Scholar
Wlezian, R. W. & Kibens V. 1985 Noise-related shear-layer dynamics in annular jets. AIAA J. 23, 715–722.Google Scholar
Yule A. J. 1973 Large scale structure in the mixing layer of a round jet. J. Fluid Mech. 89, 413–532.Google Scholar