Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-19T08:04:01.940Z Has data issue: false hasContentIssue false
  • English
  • Français

Vortex dynamics in a plane, moderate-Reynolds-number shear layer

Published online by Cambridge University Press:  26 April 2006

E. Panides  and
R. Chevray
E. Panides
Affiliation:
Mechanical Engineering Sciences Laboratory, North Tarrytown, NY 10591, USA
R. Chevray
Affiliation:
Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

A completely non-intrusive technique, utilizing synchronized flow visualization and one-point, two-component laser-Doppler velocimetry, has been developed to examine the vortical structure of a homogeneous plane shear layer at a moderate Reynolds number. Results include ensemble-averaged velocity and vorticity maps and, derived from these data, zone-averaged statistics of the basic structure, at 6.2 initial wavelengths downstream of the splitter-plate trailing edge. The velocity field data paint a clear picture of the processes involved in the engulfment or entrainment of free-stream irrotational fluid by the vortices, and the evolution of the material interface separating fluid from the two free streams. The ensemble-averaged vorticity distribution is seen to be of an elliptical cross-section, closely resembling that of the Stuart vortex for a vorticity distribution parameter of 0.4. The effect of jitter which, in the case of zone averages is effectively removed, is assessed by comparison to conventional mean flow properties. It is found that vortex jitter greatly influences u′ and Ruu and, in confirmation of previous results, that a passive vortex does not contribute to the production of large-scale Reynolds stress.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 214 , May 1990 , pp. 411 - 435
Copyright
© 1990 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

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. 1974 On density effects and large structure in turbulent mixing layers. J. Fluid Mech. 64, 755–816.Google Scholar
Chevray, R. & Tutu, N. K. 1978 Intermittency and preferential transport of heat in a round jet. J. Fluid Mech. 88, 133–160.Google Scholar
Coles, D. 1981 Prospects for useful research on coherent structure in turbulent shear flow. Proc. Indian Acad. Sci. (Engng Sci.) 4, 111–127.Google Scholar
Davis, P. O. A. L. & Yule, A. J. 1975 Coherent structures in turbulence. J. Fluid Mech. 69, 513–537.Google Scholar
Dimotakis, P. E. 1986 Two-dimensional shear layer entrainment. AIAA J. 24, 1791–1796.Google Scholar
Dimotakis, P. E. & Brown, G. L. 1976 The mixing layer at high Reynolds number: large structure dynamics and entrainment. J. Fluid Mech. 78, 535–560.Google Scholar
Dimotakis, P. E., Debussy, F. D. & Koochesfahani, M. M. 1981 Particle streak velocity field measurements in a two dimensional mixing layer. Phys. Fluids 24, 995–999.Google Scholar
Hernan, M. A. & Jimenez, L. 1982 Computer analysis of a high speed film of the plane turbulent mixing layer. J. Fluid Mech. 119, 323–345.Google Scholar
Ho, C. M. & Huang, S. 1982 Subharmonics and vortex merging in mixing layers. J. Fluid Mech. 119, 443–473.Google Scholar
Hussain, A. K. M. F. 1983 Coherent structures – reality and myth. Phys. Fluids 26, 2816–2850.Google Scholar
Hussain, A. K. M. F. & Zaman, K. B. M. Q. 1978 The free shear layer tone phenomenon and Kon interference. J. Fluid Mech. 87, 349–383.Google Scholar
J. H. 1976 An experimental investigation of mixing in two dimensional turbulent shear flows with applications to diffusion limited chemical reactions. Ph.D. thesis, California Institute of Technology.
Koochesfahani, M. M., Catherasoo, C. J., Dimotakis, P. E., Gharib, M. & Lang, D. B. 1979 Two-point LDV measurements in a plane mixing layer. AIAA J. 17, 1347–1351.Google Scholar
Moore, D.W. & Saffman, P. G. 1975 The density of organized vortices in a turbulent mixing layer. J. Fluid Mech. 69, 465–473.Google Scholar
Mumford, J. C. 1982 The structure of the large eddies in fully developed turbulent shear flows. Part 1. The plane jet. J. Fluid Mech. 118, 214–268.Google Scholar
Panides, E. 1987 On the vortical structure of a plane shear layer. Ph.D. thesis, Columbia University.
Roberts, F. A. 1985 Effects of a periodic disturbance on structure and mixing in turbulent shear layers and wakes. Ph.D. thesis, California Institute of Technology.
Sokolov, M., Kleis, S. J. & Hussain, A. K. M. F. 1981 Coherent structures induced by two simultaneous sparks in an axisymmetric jet. AIAA J. 19, 1000–1008.Google Scholar
Stuart, J. T. 1967 On finite amplitude oscillations in laminar mixing layers. J. Fluid Mech. 29, 417–440.Google Scholar
Winant, C. D. & Browand, F. K. 1974 Vortex pairing: the mechanism of turbulent mixing layer growth at a moderate Reynolds number. J. Fluid Mech. 63, 237–255.Google Scholar
Yule, A. J. 1978 Large scale structure in the mixing layer of a round jet. J. Fluid Mech. 89, 413–432.Google Scholar
Zaman, K. B. M. Q. & Hussain, A. K. M. F. 1980 Vortex pairing in a circular jet under controlled excitation. J. Fluid Mech. 101, 449–544.Google Scholar
Zaman, K. B. M. Q. & Hussain, A. K. M. F. 1981 Taylor hypothesis and large-scale coherent structures. J. Fluid Mech. 112, 379–396.Google Scholar