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A statistical model of turbulence in two-dimensional mixing layers

Published online by Cambridge University Press:  19 April 2006

Christopher K. W. Tam
Affiliation:
Department of Mathematics, Florida State University, Tallahassee
K. C. Chen
Affiliation:
Department of Mathematics, Florida State University, Tallahassee

Abstract

A statistical model based on the proposition that the turbulence of a fully developed two-dimensional incompressible mixing layer is in a state of quasi-equilibrium is developed. In this model the large structures observed by Brown & Roshko (1974) which will be assumed to persist into the fully developed turbulent region are represented by a superposition of the normal wave modes of the flow with arbitrary random amplitudes. The turbulence at a point in the flow is assumed to be dominated by the fluctuations associated with these large structures. These structures grow and amalgamate as they are convected in the flow direction. Because of the lack of intrinsic length and time scales the turbulence in question can, therefore, be regarded as created or initiated at an upstream point, the virtual origin of the mixing layer, by turbulence with a white noise spectrum and are subsequently convected downstream. The model is used to predict the second-order turbulence statistics of the flow including single point turbulent Reynolds stress distribution, intensity of turbulent velocity components, root-mean-square turbulent pressure fluctuations, power spectra and two-point space-time correlation functions. Numerical results based on the proposed model compare favourably with available experimental measurements. Predictions of physical quantities not yet measured by experiments, e.g. the root-mean-square pressure distribution across the mixing layer, are also made. This permits the present model to be further tested experimentally.

Type
Research Article
Copyright
© 1979 Cambridge University Press

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References

Bark, F. H. 1975 On the wave structure of the wall region of a turbulent boundary layer. J. Fluid Mech. 70, 229250.Google Scholar
Batt, R. G. 1975 Some measurements on the effect of tripping the two dimensional shear layer. A.I.A.A. J. 13, 245247.Google Scholar
Bradshaw, P. 1966 The effect of initial conditions on the development of a free shear layer. J. Fluid Mech. 26, 225236.Google Scholar
Brown, G. L. & Roshko, A. 1974 On density effects and large structure in turbulent mixing layers. J. Fluid Mech. 64, 775816.Google Scholar
Champagne, F. H., Pao, Y. H. & Wygnanski, I. J. 1976 On the two dimensional mixing region. J. Fluid Mech. 74, 209250.Google Scholar
Chan, Y. Y. 1974a Spatial waves in turbulent jets. Phys. Fluids 17, 4653.Google Scholar
Chan, Y. Y. 1974b Spatial waves in turbulent jets. Part II. Phys. Fluids 17, 16671670.Google Scholar
Chan, Y. Y. 1976 Spatial waves of higher modes in an axisymmetric turbulent jet. Phys. Fluids 19, 20422043.Google Scholar
Chan, Y. Y. 1977 Wavelike eddies in a turbulent jet. A.I.A.A. J. 15, 9921001.Google Scholar
Chandrsuda, C., Mehta, R. D., Weir, A. D. & Bradshaw, P. 1978 Effect of free-stream turbulence on large structures in turbulent mixing layers. J. Fluid Mech. 85, 693704.Google Scholar
Dimotakis, P. E. & Brown, G. J. 1976 The mixing layer at high Reynolds number: Large-structure dynamics and entrainment. J. Fluid Mech. 78, 535560.Google Scholar
Ko, N. W. M. & Davies, P. O. A. L. 1971 The near field within the potential cone of subsonic cold jets. J. Fluid Mech. 50, 4971.Google Scholar
Landahl, M. 1967 A wave-guide model for turbulent shear flow. J. Fluid Mech. 29, 441459.Google Scholar
Landahl, M. 1975 Wave breakdown and turbulence. SIAM J. Appl. Mech. 28, 735756.Google Scholar
Laurence, J. C. 1956 Intensity, scale and spectra of turbulence in mixing regions of free subsonic jets. Intensity, scale and spectra of turbulence in mixing regions of free subsonic jets.Rep. 1292.Google Scholar
Liepmann, H. & Laufer, J. 1947 Investigations of free turbulent mixing. N.A.C.A. Tech. Note 1257.Google Scholar
Lin, C. C. 1967 Theory of Hydrodynamic Stability. Cambridge University Press.
Malkus, W. V. R. 1956 Outline of a theory of turbulent shear flow. J. Fluid Mech. 1, 521539.Google Scholar
Moore, C. J. 1977 The role of shear layer instability waves in jet exhaust noise. J. Fluid Mech. 80, 321367.Google Scholar
Patel, R. P. 1973 An experimental study of a plane mixing layer. A.I.A.A. J. 11, 6771.Google Scholar
Roshko, A. 1976 Structure of turbulent shear flows: A new look. A.I.A.A.J. 14, 13491357.Google Scholar
Townsend, A. A. 1956 The Structure of Turbulent Shear Flow. Cambridge University Press.
Winant, C. D. & Browand, F. K. 1974 Vortex pairing: the mechanism of turbulent mixing layer growth at moderate Reynolds numbers. J. Fluid Mech. 63, 237255.Google Scholar
Wygnanski, I. & Fiedler, H. E. 1970 The two-dimensional mixing region. J. Fluid Mech. 41, 327361.Google Scholar