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Two-dimensional turbulent wakes

Published online by Cambridge University Press:  28 March 2006

Ian S. Gartshore
Affiliation:
Department of Mechanical Engineering, McGill University

Abstract

The equations of mean motion indicate that two-dimensional turbulent wakes, when subjected to appropriately tailored adverse pressure gradients, can be self-preserving. An experimental examination of two nearly self-preserving wakes is reported here. Mean velocity, longitudinal and lateral turbulence intensity, inter-mittency and shear stress distributions have been measured and are compared with Townsend's data from the small-deficit undistorted wake. In comparison with the undistorted case, the present wakes have slightly lower turbulent intensities and significantly lower shear stresses, all quantities being non-dimensionalized by a local velocity scale taken as the maximum mean velocity deficit. A consideration of the reasons for the shear stress reduction leads to an expression from which the shear stresses in any symmetrical free equilibrium shear flow can be found. This relationship is used to calculate the rate of growth in the measured wakes, with reasonable success.

Type
Research Article
Copyright
© 1967 Cambridge University Press

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References

Bradshaw, P. 1966 The turbulence structure of equilibrium boundary layers. N.P.L. Aero. Rept. no. 1184.
Clauser, F. M. 1956 The turbulent boundary layer. Advances in Applied Mechanics, vol. 4. New York: Academic Press.
Gartshore, I. S. 1965 An experimental examination of the large-eddy equilibrium hypothesis. J. Fluid Mech. 24, 89.Google Scholar
Grant, H. L. 1958 The large eddies of turbulent motion. J. Fluid Mech. 4, 149.Google Scholar
Keffer, J. F. 1965 The uniform distortion of a turbulent wake. J. Fluid Mech. 22, 135.Google Scholar
Newman, B. G. 1965 Turbulent jets and wakes in a pressure gradient. Proc. G.M. Conference, Detroit. Elsevier Publishing Co.
Patel, R. P. & Newman, B. G. 1961 Self-preserving, two-dimensional turbulent jets and wall jets in a moving stream. McGill University, MERL Rept. Ae 5.
Reynolds, A. J. 1962 Observations on distorted turbulent wakes. J. Fluid Mech. 13, 333.Google Scholar
Townsend, A. A. 1949 The fully developed turbulent wake of a circular cylinder. Aust. J. Sci. Res. 2, 451.Google Scholar
Townsend, A. A. 1956a The Structure of Turbulent Shear Flow. Cambridge University Press.
Townsend, A. A. 1956b The properties of equilibrium boundary layers. J. Fluid Mech. 1, 561.Google Scholar