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The effects of excitation on the coherent and random motion in a plane wall jet

Published online by Cambridge University Press:  26 April 2006

M. D. Zhou ,
C. Heine  and
I. Wygnanski
M. D. Zhou
Affiliation:
Department of Aerospace Engineering, The University of Arizona, AZ 85721, USA
C. Heine
Affiliation:
Department of Aerospace Engineering, The University of Arizona, AZ 85721, USA
I. Wygnanski
Affiliation:
Department of Aerospace Engineering, The University of Arizona, AZ 85721, USA
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Abstract

Three components of velocity fluctuations were measured in a plane turbulent wall jet which was modulated periodically by a sinusoidal pressure fluctuation in its settling chamber. The experiment was carried out in a closed-loop wind tunnel in the absence of an external stream at Reynolds number Rej = Ujb/v = 6900 and Strouhal number Stj = fb/Uj = 9.5 × 10−3, where b is the width of the slot from which the jet emerges at an efflux velocity Uj. A detailed comparison is provided with similar measurements made in a natural, unexcited turbulent wall jet. One of the purposes of this experiment was to establish the kinetic energy transfers which take place in the wall jet under controlled perturbations. More specifically, we were interested in determining the interactions occurring between the steady mean flow, the coherent eddies and the ‘random’ turbulent fluctuations. We used the triple decomposition of the equations of motion as suggested by Hussain (1983) and quickly observed that the usefulness of this decomposition depends on the definition of coherent motion, which is ambiguous in the presence of phase jitter. Two such definitions were considered and the results are discussed in the experimental case-study provided. An attempt is made to define quantitatively the intensities of the coherent motion in externally excited, wallbounded flows. It is a case-study and not a parametric investigation aimed at maximizing the effects of period oscillations on the wall jet.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 310 , 10 March 1996 , pp. 1 - 37
Copyright
© 1996 Cambridge University Press

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References

Alcaraz, E. 1977 Contribution a l'etude d'un jet plan turbulent evolaunt le long d'une parios convexe a faible courbure. These d'Etat. Université Claude Bernard, Lyon, France.
Blackwelder, R. F. & Kaplan, R. E. 1972 The intermittent structure of the wall region in a turbulent boundary layer. Proc. 12th IUTAM Intl Congr. of Applied Mechanics Moscow.
Glezer, A., Katz, Y. & Wygnanski, I. 1989 On the breakdown of a wave packet trailing a turbulent spot in a laminar boundary layer. J. Fluid Mech. 198, 1.Google Scholar
Guitton, D. E. & Newman, B. G. 1977 Self preserving turbulent wall jets over convex surfaces. J. Fluid Mech. 81, 155.Google Scholar
Heine, C. 1994 The energy budget in the forced turbulent wall jet. Dipl. Ing. Thesis, Technical University, Berlin.
Heskestadt, G. 1965 The plane turbulent jet. Trans. ASME E: Appl. Mech. 32, 721.Google Scholar
Hinze, J. O. 1975 Turbulence. McGraw Hill.
Hussain, A. K. M. F. 1983 Coherent structures – reality and myth. Phys. Fluids 26, 2816.Google Scholar
Irwin, H. P. A. H. 1973 Measurements in a self preserving plane wall jet in a positive pressure gradient. J. Fluid Mech. 61, 33.Google Scholar
Karlsson, R. I., Ericsson, J. & Persson, J. 1992 LDV measurements of a plane wall jet in a large enclosure. Internal Rep. Department of Hydromechanics, Royal Institute of Technology, Sweden.
Katz, Y., Horev, E. & Wygnanski, I. 1992 The forced turbulent wall jet. J. Fluid Mech. 242, 577 (referred to herein as KHW).Google Scholar
Klebanoff, P. S. 1955 Characteristics of turbulence in a boundary layer with zero pressure gradient. NACA Rep. 1247.
Kruka, V. & Eskinazi, S. 1964 The wall jet in a moving stream. J. Fluid Mech. 20, 555.Google Scholar
Laufer, J. 1954 The structure of turbulence in a fully developed pipe flow. NACA Rep. 1174.
Launder, B. E. & Rodi, W. 1981 The turbulent wall jets. Prog. Aerospace Sci. 19, 81.Google Scholar
Narasimha, R., Narayan, K. Y. & Parthasarathy, S. P. 1973 Parametric analysis of turbulent wall jets in still air. Aero. J. 77, 355.Google Scholar
Oster, D. & Wygnanski, I. 1982 The forced mixing layer between parallel streams. J. Fluid Mech. 123, 91.Google Scholar
Rotta, J. C. 1962 Turbulent boundary layer in incompressible flow. Prog. Aero. Sci. 2, 1–219.Google Scholar
Tailland, A. & Mathieu, J. 1967 Jet parietal. J. Méc. 6, 103.Google Scholar
Tennekes, H. & Lumley, J. L. 1972 A First Course in Turbulence. MIT Press
Wygnanski, I., Haritonidis, J. H. & Kaplan, R. E. 1979 On a Tollmien-Schlichting wave packet produced by a turbulent spot. J. Fluid Mech. 92, 505.Google Scholar
Wygnanski, I., Katz, Y. & Horev, E. 1992 On the applicability of various scaling laws to the turbulent wall jet. J. Fluid Mech. 234, 669.Google Scholar
Zhou, M. D., Heine, C. & Wygnanski, I. 1993 The forced wall jet in an external stream. Proc. AIAA Shear Flow Conf. Orlando. AIAA Paper 93-3250.
Zhou, M. D. & Wygnanski, I. 1993 Parameters governing the turbulent wall jet in an external stream. AIAA J. 31, 848 (referred to herein as ZW).Google Scholar