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Turbulence memory in self-preserving wakes

Published online by Cambridge University Press:  19 April 2006

Paul M. Bevilaqua  and
Paul S. Lykoudis
Paul M. Bevilaqua
Affiliation:
School of Aeronautics, Astronautics and Engineering Sciences, Purdue University, West Lafayette, Indiana 47907 Present address: Rockwell International, Columbus Aircraft Division, Columbus, Ohio 43216.
Paul S. Lykoudis
Affiliation:
School of Aeronautics, Astronautics and Engineering Sciences, Purdue University, West Lafayette, Indiana 47907 Present address: School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907.
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Abstract

The persistence of the large vortices formed at the origin of wakes and mixing layers constitutes a kind of memory of initial conditions by the turbulence. In order to study the fading of this turbulence memory, and its effect on the rate of approach to the fully developed state, two wakes with different initial conditions have been examined experimentally. The wake of a sphere was compared with the wake of a porous disk which had the same drag, but did not exhibit vortex shedding. Measurements were made of the mean and fluctuating velocities, the anisotropy of the turbulence, and the intermittency. It was found that the wake of the sphere developed self-preserving behaviour more rapidly than the wake of the disk, and that even after both wakes became self-preserving there were differences between them in the structure of the turbulence and the scale of the mean flow. From this it is concluded that the behaviour of self-preserving wakes does not depend on the drag alone, but also on the structure of the dominant eddies. Generalizing these results, it is suggested that reported differences in the value of the entrainment constant of jets, wakes, and mixing layers are due to differences in the structure of the dominant eddies, rather than differences in the type of flow.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 89 , Issue 3 , 13 December 1978 , pp. 589 - 606
Copyright
© 1978 Cambridge University Press

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References

Achenbach, E. 1974 Vortex shedding from spheres. J. Fluid Mech. 62, 209–221.Google Scholar
Achenbach, E. 1974 Effects of surface roughness and tunnel blockage on the flow past spheres. J. Fluid Mech. 65, 113–125.Google Scholar
Baldwin, L. V. & Sandborn, V. A. 1968 Intermittency of far wake turbulence. A.I.A.A. J. 6, 1163–1164.Google Scholar
Bevilaqua, P. M. 1973 Intermittency, the entrainment problem. Ph.D. thesis, Purdue University.
Bevilaqua, P. M. & Lykoudis, P. S. 1971 Mechanism of entrainment in turbulent wakes. A.I.A.A. J. 9, 1657–1659.Google Scholar
Brown, G. L. & Roshko, A. 1971 Effect of density differences on the turbulent mixing layer. Turbulent Shear Flows. AGARD Conf. Proc. no. 93, paper 23, pp. 1–12.Google Scholar
Carmody, T. 1963 Establishment of the wake behind a disk. Ph.D. thesis, State University of Iowa.
Castro, I. P. 1971 Wake characteristics of two-dimensional perforated plates normal to an air stream. J. Fluid Mech. 46, 599–609.Google Scholar
Champagne, B. H. 1967 Turbulence measurements with inclined hot wires. J. Fluid Mech. 28, 177–182.Google Scholar
Fremuth, P. & Uberoi, M. S. 1973 Temperature fluctuations in the turbulent wake behind an optically heated sphere. Phys. Fluids 16, 161–168.Google Scholar
Gartshore, I. S. 1966 Experimental examination of the large eddy equilibrium hypothesis. J. Fluid Mech. 24, 89–98.Google Scholar
Gibson, C. H., Chen, C. C. & Lin, S. C. 1968 Measurements of turbulent velocity and temperature fluctuations in the wake of a sphere. A.I.A.A. J. 6, 642–649.Google Scholar
Grant, H. L. 1958 Large eddies of turbulent motion. J. Fluid Mech. 4, 149–190.Google Scholar
Hwang, N. H. & Baldwin, L. V. 1966 Decay of turbulence in axisymmetric wakes. A.S.M.E. J. Basic Engng, March, pp. 261–268.Google Scholar
Kibens, V. R. 1968 Intermittent region of a turbulent boundary layer. Ph.D. thesis, Johns Hopkins University.
Kline, S. J., Reynolds, W. C., Schraub, F. A. & Runstadler, P. W. 1967 Structure of turbulent boundary layers. J. Fluid Mech. 30, 741–773.Google Scholar
Konrad, J. H. 1976 Experimental investigation of mixing in shear layers and wakes. Ph.D. thesis, California Institute of Technology, Pasadena, California
Narasimha, R. & Prabhu, A. 1972 Equilibrium and relaxation in wakes. J. Fluid Mech. 54, 1–17.Google Scholar
Oswald, L. J. & Kibens, V. R. 1971 Turbulent flow in the wake of a disk. Univ. Michigan Tech. Rep. no. 002820.Google Scholar
Pao, H. P. & Kao, T. W. 1977 Vortex structure in the wake of a sphere. Phys. Fluids 20, 187–191.Google Scholar
Papailiou, D. D. 1971 Turbulent vortex streets. Ph.D. thesis, Purdue University.
Papailiou, D. D. & Lykoudis, P. S. 1974 Turbulent vortex streets and the mechanism of entrainment. J. Fluid Mech. 62, 11–31.Google Scholar
Reynolds, A. J. 1974 Turbulent Flows in Engineering. Wiley.
Riddhagni, P. R., Bevilaqua, P. M. & Lykoudis, P. S. 1971 Measurements in the turbulent wake of a sphere. A.I.A.A. J. 9, 1433–1434.Google Scholar
Stewart, R. W. & Townsend, A. A. 1951 Similarity and self-preservation in isotropic turbulence. Phil. Trans. Roy. Soc. A 243, 359–386.Google Scholar
Tennekes, H. & Lumley, J. L. 1972 First Course in Turbulence. MIT Press.
Townsend, A. A. 1949 Fully developed turbulent wake of a circular cylinder. Australian J. Sci. Res. 2, 451–468.Google Scholar
Townsend, A. A. 1956 Structure of Turbulent Shear Flow. Cambridge University Press.
Townsend, A. A. 1970 Entrainment and the structure of turbulent flow. J. Fluid Mech. 41, 13–46.Google Scholar
Townsend, A. A. 1976 Structure of Turbulent Shear Flow, 2nd edn. Cambridge University Press.
Uberoi, M. S. & Freymuth, P. 1970 Turbulent energy balance and spectra of the axisymmetric wake. Phys. Fluids 13, 2205–2210.Google Scholar