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The turbulent mixing layer: geometry of large vortices

Published online by Cambridge University Press:  20 April 2006

F. K. Browand  and
T. R. Troutt
F. K. Browand
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089-0192
T. R. Troutt
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089-0192 Permanent address: Department of Mechanical Engineering, Washington State University, Pullman, WA 99164-2920.
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Abstract

Several means for visualizing large-scale vortex structure in a turbulent mixing layer are proposed. Most of the observations are recorded along the low-speed side of the mixing layer, external to the rotational portion of the flow. Conventional correlation measurements in both the streamwise and spanwise directions indicate that the vortex structure becomes independent of the downstream coordinate in a non-dimensional distance of order λx/θi = 300–400, where $\lambda = \Delta U/2\overline{U}$ is the speed ratio and θi is the initial integral thickness. Simultaneous hot-wire measurements at 12 spanwise positions allow computer reconstruction of the velocity field as a function of span and time. These visualizations show the vortex structures to be primarily aligned across the span of the flow, but to contain irregularities. Spanwise correlation lengths are of the order of 3–5δω (δω is the local vorticity thickness). However, the large vortices typically have lengths of order 20δω when the irregularities along the span are ignored.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 158 , September 1985 , pp. 489 - 509
Copyright
© 1985 Cambridge University Press

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References

Bernal L. P. 1981 The coherent structure of turbulent mixing layers. I. Similarity of the primary vortex structure. II. Secondary streamwise vortex structure. Ph.D. thesis. California Institute of Technology.
Bernal L. P., Breidenthal R. E., Brown G. L., Konrad, J. H. & Roshko A. 1979 On the development of three-dimensional small scales in turbulent mixing layers. Proc. 2nd Turbulent Shear Flow Symp., Lond.
Breidenthal R. E. 1981 Structure in turbulent mixing layers and wakes using a chemical reaction. J. Fluid Mech. 109, 1–24.Google Scholar
Browand, F. K. & Ho C. M. 1983 The mixing layer: an example of quasi two-dimensional turbulence. Two-Dimensional Turbulence: J. Méc. Théor. Appl. Special Suppl., pp. 99–120.
Browand, F. K. & Latigo B. O. 1979 Growth of the two-dimensional mixing layer from a turbulent and non-turbulent boundary layer. Phys. Fluids 22, 1011–1019.Google Scholar
Browand, F. K. & Troutt T. R. 1980 A note on spanwise structure in the two-dimensional mixing layer. J. Fluid Mech. 97, 771–781.Google Scholar
Browand, F. K. & Weidman P. D. 1976 Large scales in the developing mixing layer. J. Fluid Mech. 76, 127–144.Google Scholar
Brown, G. L. & Roshko A. 1971 The effect of density difference on the turbulent mixing layer. AGARD-CP-93, pp. 23–35.
Brown, G. L. & Roshko A. 1974 On density effects and large structure in turbulent mixing layers. J. Fluid Mech. 64, 775–816.Google Scholar
Ho, C. M. & Huang L. S. 1982 Subharmonics and vortex merging in mixing layers. J. Fluid Mech. 119, 443–473.Google Scholar
Ho, C. M. & Huerre P. 1984 Perturbed free shear layers. Ann. Rev. Fluid Mech. 16, 365–423.Google Scholar
Hussain, A. K. M. F. & Zaman K. B. M. Q. 1981 The ‘preferred mode’ of the axisymmetric jet. J. Fluid Mech. 110, 39–71.Google Scholar
Jimenez J., Martinez-Val, R. & Rebollo M. 1979 On the origin and evolution of three-dimensional effects in the mixing layer. Univ. Politec. Madrid, Internal Rep. DA-ERO-79-G-079.Google Scholar
Konard J. H. 1976 An experimental investigation of mixing in two-dimensional turbulent shear flows with applications to diffusion-limited chemical reactions. Caltech. Internal Rep. CIT-8-PU.Google Scholar
Koop, C. G. & Browand F. K. 1979 Instability and turbulence in a stratified fluid with shear. J. Fluid Mech. 93, 135–159.Google Scholar
Monkewitz, P. A. & Huerre P. 1982 The influence of the velocity ratio on the spatial instability of mixing layers. Phys. Fluids 25, 1137–1143.Google Scholar
Winant, C. D. & Browand F. K. 1974 Vortex pairing, the mechanism of turbulent mixing layer growth at moderate Reynolds number. J. Fluid Mech. 63, 237–255.Google Scholar
Wood, D. H. & Bradshaw P. 1982 A turbulent mixing layer constrained by a solid surface. Part 1. Measurements before reaching the surface. J. Fluid Mech. 122, 57–89.Google Scholar
Wygnanski, I. & Fiedler H. E. 1970 The two-dimensional mixing region. J. Fluid Mech. 41, 327–361.Google Scholar
Wygnanski, I. & Oster D. 1982 The forced mixing layer between parallel streams. J. Fluid Mech. 123, 91–130.Google Scholar