Hostname: page-component-848d4c4894-sjtt6 Total loading time: 0 Render date: 2024-06-29T06:09:35.035Z Has data issue: false hasContentIssue false
  • English
  • Français

The evolution of the coherent structures in a uniformly distorted plane turbulent wake

Published online by Cambridge University Press:  26 April 2006

G. A. Kopp ,
J. G. Kawall  and
J. F. Keffer
G. A. Kopp
Affiliation:
Department of Mechanical Engineering, University of Toronto, Toronto, Canada, M5S 1A4
J. G. Kawall
Affiliation:
Department of Mechanical Engineering, University of Toronto, Toronto, Canada, M5S 1A4
J. F. Keffer
Affiliation:
Department of Mechanical Engineering, University of Toronto, Toronto, Canada, M5S 1A4
Get access Rights & Permissions [Opens in a new window]

Abstract

A plane turbulent wake generated by a flat plate is subjected to a uniform distortion. It is observed that nearly two-dimensional, quasi-periodic coherent structures dominate the distorted wake. Rapid distortion theory, applied to a kinematic vortex model of the coherent structures in the undistorted far wake, predicts many of the effects revealed by a hot-wire anemometry/pattern-recognition analysis of these structures. Specifically, rapid distortion theory predicts reasonably well the observed changes in the ensemble-averaged velocity patterns and the disproportionate amplification of the large-scale coherent structures relative to the smaller-scale ‘isotropic’ eddies. These results are consistent with the view that self-preservation of the distorted wake is not possible because of the selective amplification of the coherent structures, which control the development of the wake. As well, the entrainment rate in the distorted wake increases at a rate greater than that predicted by the self-preservation theory.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 291 , 25 May 1995 , pp. 299 - 322
Copyright
© 1995 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

Batchelor, G. K. & Proudman, I. 1954 The effect of rapid distortion of a fluid in turbulent motion. Q. J. Mech. Appl. Maths 7, 83–103.Google Scholar
Bisset, D. K., Antonia, R. A. & Browne, L. W. B. 1990 Spatial organization of large structures in the turbulent far wake of a cylinder. J. Fluid Mech. 218, 439–461.Google Scholar
Budny, R. S., Kawall, J. G. & Keffer, J. F. 1979 Vortex street evolution in the wake of a circular cylinder. Second Symp. on Turbulent Shear Flows, Imperial College, pp. 7.20–7.25.
Davies, M. E. 1976 A comparison of the wake structure of a stationary and oscillating bluff body, using a conditional averaging technique. J. Fluid Mech. 75, 209–231.Google Scholar
Elliot, C. J. & Townsend, A. A. 1981 The development of a turbulent wake in a distorting duct. J. Fluid Mech. 113, 433–467.Google Scholar
Ferré, J. A. & Giralt, F. 1989a Pattern-recognition analysis of the velocity field in plane turbulent wakes. J. Fluid Mech. 198, 27–64.Google Scholar
Ferré, J. A. & Giralt, F. 1989b Some topological features of the entrainment process in a heated turbulent wake. J. Fluid Mech. 198, 65–78.Google Scholar
Ferré, J. A., Mumford, J. C., Savill, A. M. & Giralt, F. 1990 Three-dimensional large-eddy motions and fine-scale activity in a plane turbulent wake. J. Fluid Mech. 210, 371–414.Google Scholar
Giralt, F. & Ferré, J. A. 1993 Structure and flow patterns in turbulent wakes. Phys. Fluids A 5, 1783–1789.Google Scholar
Grant, H. L. 1958 The large eddies of turbulent motion. J. Fluid Mech. 4, 149–190.Google Scholar
Huang, Z., Ferré, J. A., Kawall, J. G. & Keffer, J. F. 1993 The evolution of coherent structures in the plane turbulent wake of a porous body. 3rd World Conf. on Exp. Heat Transfer, Fluid Mech. and Thermodynamics, Honolulu, pp. 1001–1108.
Hunt, J. C. R. & Mulhearn, P. J. 1973 Turbulent dispersion from sources near two-dimensional obstacles. J. Fluid Mech. 61, 245–274.Google Scholar
Kawall, J. G. & Keffer, J. F. 1982 The role of coherent structures in the development of a uniformly strained turbulent wake. Turbulent Shear Flows 3 (ed. L. J. S. Bradbury et al.), pp. 132–145. Springer.
Keffer, J. F. 1965 The uniform distortion of a turbulent wake. J. Fluid Mech. 22, 135–159.Google Scholar
Keffer, J. F., Kawall, J. G., Hunt, J. C. R. & Maxey, M. R. 1978 The uniform distortion of thermal and velocity mixing layers. J. Fluid Mech. 86, 465–490.Google Scholar
Kopp, G. A., Kawall, J. G. & Keffer, J. F. 1995 A diagnostic experimental technique for studying coherent structures in plane turbulent wakes. In Flow Measurement and Instrumentation, vol. 6 (in press).
Lamb, H. 1932 Hydrodynamics. Cambridge University Press.
Reynolds, A. J. 1962 Observations on distorted turbulent wakes. J. Fluid Mech. 13, 333–355.Google Scholar
Taylor, G. I. 1935 Turbulence in a contracting stream. Z. Angew. Math. Mech. 15, 91–96.Google Scholar
Townsend, A. A. 1954 The uniform distortion of homogeneous turbulence. Q. J. Mech. App. Maths 7, 104–127.Google Scholar
Townsend, A. A. 1966 The mechanism of entrainment in free turbulent flows. J. Fluid Mech. 26, 689–715.Google Scholar
Townsend, A. A. 1970 Entrainment and the structure of turbulent flow. J. Fluid Mech. 41, 13–46.Google Scholar
Townsend, A. A. 1980 The response of shared turbulence to additional distortion. J. Fluid Mech. 81, 171–91.Google Scholar
Tucker, H. J. & Reynolds, A. J. 1968 The distortion of turbulence by irrotational plane strain. J. Fluid Mech. 32, 657–673.Google Scholar