Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-10T06:32:30.378Z Has data issue: false hasContentIssue false
  • English
  • Français

A ‘turbulent spot’ in an axisymmetric free shear layer. Part 1

Published online by Cambridge University Press:  19 April 2006

M. Sokolov ,
A. K. M. F. Hussain ,
S. J. Kleis  and
Z. D. Husain
M. Sokolov
Affiliation:
Department of Mechanical Engineering, University of Houston, Texas 77004
A. K. M. F. Hussain
Affiliation:
Department of Mechanical Engineering, University of Houston, Texas 77004
S. J. Kleis
Affiliation:
Department of Mechanical Engineering, University of Houston, Texas 77004
Z. D. Husain
Affiliation:
Department of Mechanical Engineering, University of Houston, Texas 77004
Get access Rights & Permissions [Opens in a new window]

Abstract

A three-dimensional ‘turbulent spot’ has been induced in the axisymmetric free mixing layer of a 12.7 cm diameter air jet by a spark generated at the nozzle boundary layer upstream of the exit. The spot coherent-structure signature, buried in the large-amplitude random fluctuating signal, has been educed at three downstream stations within the apparent self-preserving region of the mixing layer (i.e. x/D = 1.5, 3.0 and 4.5) at the jet exit speed of 20 ms−1. The eduction has been performed through digital phase averaging of the spot signature from 200 realizations. In order to reduce the effect of the turbulence-induced jitter on the phase average, individual filtered signal arrays were optimally time-aligned through an iterative process of cross-correlation of each realization with the ensemble average. Further signal enhancement was achieved through rejection of realizations requiring excessive time shifts for alignment. The number of iterations required and the fraction of realizations rejected progressively increase with the downstream distance and the radial position.

The mixing-layer spot is a large-scale elongated structure spanning the entire width of the layer but does not appear to exhibit a self-similar shape. The dynamics of the mixing-layer spot and its eduction are more complicated than those of the boundary-layer spot. The spot initially moves downstream essentially at a uniform speed across the mixing layer, but further downstream it accelerates on the high-speed side and decelerates on the low-speed side. This paper discusses the data acquisition and processing techniques and the results based on the streamwise velocity signals. Phase average distributions of vorticity, pseudo-streamlines, coherent and background Reynolds stresses and further dynamics of the spot are presented in part 2 (Hussain, Kleis & Sokolov 1980).

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 98 , Issue 1 , 15 May 1980 , pp. 65 - 95
Copyright
© 1980 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

Abramovich, G. N. 1963 The Theory of Turbulent Jets. M.I.T.
Acton, E. 1978 Structure and Mechanisms of Turbulence I, vol. 75 (ed. H. Fiedler), Lecture notes in physics, p. 162. Springer.
Batt, R. G. 1975 A.I.A.A. J. 13, 245.
Bechert, D. & Pfizenmaier, E. 1975 J. Fluid Mech. 72, 341.
Birch, S. F. & Eggers, J. M. 1973 N.A.S.A. SP-321, p. 11.
Bradshaw, P. 1966 J. Fluid Mech. 26, 225.
Brown, G. L. & Roshko, A. 1974 J. Fluid Mech. 64, 775.
Bruun, H. H. 1977 J. Fluid Mech. 64, 775.
Cantwell, B. J., Coles, D. & Dimotakis, P. 1978 J. Fluid Mech. 87, 641.
Champagne, F. H., Pao, Y. H. & Wygnanski, I. J. 1976 J. Fluid Mech. 74, 209.
Chandrsuda, C., Mehta, R. D., Weir, A. D. & Bradshaw, P. 1978 J. Fluid Mech. 85, 693.
Clark, A. R. 1974 M.S. thesis, University of Houston.
Clark, A. R. 1979 Ph.D. dissertation, University of Houston.
Coles, D. & Barker, S. J. 1975 Turbulent Mixing in Nonreactive and Reactive Flows (ed. S. N. B. Murthy), p. 285. Plenum.
Crow, S. C. & Champagne, F. H. 1971 J. Fluid Mech. 48, 547.
Davies, P. O. A. L. & Baxter, D. R. J. 1978 Structure and Mechanisms of Turbulence I, vol. 75 (ed. H. Fiedler), Lecture notes in physics, p. 125. Springer.
Dimotakis, P. E. & Brown, G. L. 1976 J. Fluid Mech. 78, 535.
Ffowcs Williams, J. E. & Kempton, A. J. 1978 Structure and Mechanisms of Turbulence I, vol. 75 (ed. H. Fiedler), Lecture notes in physics, p. 125. Springer.
Fiedler, H. & Thies, H. J. 1978 Structure and Mechanisms of Turbulence I, vol. 75 (ed. H. Fiedler), Lecture notes in physics, p. 108. Springer.
Foss, J. F. 1977 Turbulent Shear Flows. Pennsylvania State Univ., 11.33.
Husain, Z. D. & Hussain, A. K. M. F. 1979 A.I.A.A. J. 17, 48.
Hussain, A. K. M. F. 1978 Structure and Mechanisms of Turbulence I, vol. 75 (ed. H. Fiedler), Lecture notes in physics, p. 103. Springer.
Hussain, A. K. M. F. & Clark, A. R. 1977 Physics Fluids 20, 1416.
Hussain, A. K. M. F., Kleis, S. J. & Sokolov, M. 1980 J. Fluid Mech. 98, 97.
Hussain, A. K. M. F. & Ramjee, V. 1976 Trans. A.S.M.E. I, J. Fluids Engng 98, 58.
Hussain, A. K. M. F. & Reynolds, W. C. 1970 J. Fluid Mech. 41, 241.
Hussain, A. K. M. F. & Zaman, K. B. M. Q. 1975 Proc. 3rd Interagency Symp. Trans. Noise, Univ. of Utah, p. 314.
Hussain, A. K. M. F. & Zaman, K. B. M. Q. 1978a Structure and Mechanisms of Turbulence I, vol. 75 (ed. H. Fiedler), Lecture notes in physics, p. 31. Springer.
Hussain, A. K. M. F. & Zaman, K. B. M. Q. 1978b J. Fluid Mech. 87, 349.
Hussain, A. K. M. F. & Zedan, M. F. 1978a Phys. Fluids 21, 1100.
Hussain, A. K. M. F. & Zedan, M. F. 1978b Phys. Fluids 21, 1475.
Kline, S. J., Reynolds, W. C., Schraub, F. A. & Runstadler, P. W. 1967 J. Fluid Mech. 30, 741.
Ko, N. W. M. & Davies, P. O. A. L. 1971 J. Fluid Mech. 50, 49.
Ko, N. W. M. & Kwan, A. S. H. 1976 J. Fluid Mech. 73, 305.
Kovasznay, L. S. G. 1978 Structure and Mechanisms of Turbulence I, vol. 75 (ed. H. Fiedler), Lecture notes in physics, p. 1. Springer.
Landahl, M. T. 1967 J. Fluid Mech. 29, 441.
Lau, J. C. & Fisher, M. J. 1975 J. Fluid Mech. 67, 229.
Liepmann, H. W. 1978 Experimental Approaches in Fluid Mechanics. Invited Lecture at 8th U.S. Nat. Cong. on Appl. Mech. UCLA.Google Scholar
Michalke, A. & Fuchs, H. V. 1975 J. Fluid Mech. 70, 179.
Mollo-Christensen, E. 1967 Trans. A.S.M.E. E, J. Appl. Mech. 89, 1.
Moore, C. J. 1977 J. Fluid Mech. 80, 321.
Moore, D. W. & Saffman, P. G. 1975 J. Fluid Mech. 69, 453.
Payne, F. R. & Lumley, J. L. 1967 Physics Fluids Suppl. 10, S194.
Phillips, O. M. 1967 J. Fluid Mech. 27, 131.
Reynolds, W. C. & Hussain, A. K. M. F. 1972 J. Fluid Mech. 52, 263.
Roshko, A. 1976 A.I.A.A. J. 10, 1349–57.
Saffman, P. G. 1978 Structure and Mechanisms of Turbulence II, vol. 76 (ed. H. Fiedler), Lecture notes in physics, p. 273. Springer.
Schlichting, H. 1968 Boundary Layer Theory. McGraw-Hill.
Schubauer, G. B. & Klebanoff, P. S. 1955 N.A.C.A. Tech. Note TN 3489.
Townsend, A. A. 1956 The Structure of Turbulent Shear Flow. Cambridge University Press.
Winant, C. D. & Browand, F. K. 1974 J. Fluid Mech. 63, 237.
Wygnanski, I., Sokolov, M. & Friedman, D. 1976 J. Fluid Mech. 78, 785.
Yule, A. J. 1977 Turb. Shear Flows. Pennsylvania State Univ., 11.13.
Zaman, K. B. M. Q. 1978 Ph.D. Dissertation, University of Houston.
Zilberman, M., Wygnanski, I. & Kaplan, R. E. 1977 Phys. Fluids Suppl. 20, S258.