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Nonlinear binary-mode interactions in a developing mixing layer

Published online by Cambridge University Press:  21 April 2006

D. E. Nikitopoulos
Affiliation:
The Division of Engineering, Brown University, Providence, RI 02912, USA
J. T. C. Liu
Affiliation:
The Division of Engineering, Brown University, Providence, RI 02912, USA

Abstract

In this paper we present the formulation and results of two-wave interactions in a spatially developing shear layer, directed at understanding and interpreting the physical mechanisms that underlie the results of quantitative observation. Our study confirms the existence of Kelly's mechanism that augments the growth of a subharmonic disturbance by extracting energy from its fundamental or vice versa. This mechanism is shown to be strongest in the region where the fundamental begins to return energy to the mean flow and the two wave modes are of comparable energy levels. It is found that the initial conditions and especially the initial phase angle between the two disturbances play a very significant role in the modal development and that of the shear layer itself. A doubling of the shear-layer thickness is shown to take place; the two successive plateaux in its growth are attributed to the peaking in the energy production rates of the fundamental and subharmonic fluctuations.

Type
Research Article
Copyright
© 1987 Cambridge University Press

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References

Alper, A. & Liu, J. T. C. 1978 On the interactions between large-scale structure and fine grained turbulence in a free shear flow. II. The development of spatial interactions in the mean. Proc. R. Soc. Lond. A 395, 497523.Google Scholar
Browand, F. K. 1966 An experimental investigation of the instability of an incompressible separated shear layer. J. Fluid Mech. 26, 281307.Google Scholar
Fiedler, H. E., Dziomba, B., Mensing, P. & Rösgen, T. 1981 Initiation, evolution and global consequences of coherent structures in turbulent shear flows. In The Role of Coherent Structures in Modelling Turbulence and Mixing (ed. J. Jimenez). Lecture Notes in Physics, vol. 136, pp. 219251. Springer.
Freymuth, P. 1966 On transition in a separated laminar boundary layer. J. Fluid Mech. 25, 683704.Google Scholar
Gaster, M., Kit, E. & Wygnanski, I., 1985 Large-scale structures in a forced turbulent mixing layer. J. Fluid Mech. 150, 2339.Google Scholar
Ho, C. M. & Huang, L. S. 1982 Subharmonics and vortex merging in mixing layers. J. Fluid Mech. 119, 443473.Google Scholar
Kelly, R. E. 1967 On the stability of an inviscid shear layer which is periodic in space and time. J. Fluid Mech. 27, 657689.Google Scholar
Lin, C. C. 1955 The Theory of Hydrodynamic Stability. Cambridge University Press.
Liu, J. T. C. 1981 Interaction between large-scale coherent structures and fine-grained turbulence in free shear flows. In Transition and Turbulence (ed. R. E. Meyer), pp. 167214. Academic.
Liu, J. T. C. 1987 Contributions to the understanding of large-scale coherent structures in developing free turbulent flows. Adv. Appl. Mech. 26 (in press).Google Scholar
Liu, J. T. C. & Lees, L. 1970 Finite amplitude instability of the compressible laminar wake. Strongly amplified disturbances. Phys. Fluids 13, 29322938.Google Scholar
Liu, J. T. C. & Merkine, L. 1976 On the interactions between large-scale structure and finegrained turbulence in a free shear flow. I. The development of temporal interactions in the mean. Proc. R. Soc. Lond. A 352, 213247.Google Scholar
Liu, J. T. C. & Nikitopoulos, D. E. 1982 Mode interactions in developing shear flows. Bull. Am. Phys. Soc. 27, 1192.Google Scholar
Mack, L. M. 1965 Computation of the stability of the laminar compressible boundary layer. Meth. Comp. Phys. 4, 274299.Google Scholar
Mankbadi, R. R. 1985 On the interaction between fundamental and subharmonic instability waves in a turbulent round jet. J. Fluid Mech. 160, 385419.Google Scholar
Miau, J.-J. & Karlsson, S. K. F. 1986 Evolution of flow in the developing region of the mixing layer with a laminar wake as initial condition. Phys. Fluids 29, 35983607.Google Scholar
Miksad, R. W. 1972 Experiments on the nonlinear stages of free shear layer transition. J. Fluid Mech. 56, 695719.Google Scholar
Miksad, R. W. 1973 Experiments on nonlinear interactions in the transition of a free shear layer. J. Fluid Mech. 59, 121.Google Scholar
Nikitopoulos, D. E. 1982 Nonlinear interaction between two instability waves in a developing shear layer. ScM thesis. Brown University, Providence, R.I.
Rue-Su Ko, D. R. S., Kubota, T. & Lees, L. 1970 Finite disturbance effect on the stability of a laminar incompressible wake behind a flat plate. J. Fluid Mech. 40, 315341.Google Scholar
Sato, H. 1959 Further investigation on the transition of two-dimensional separated layer at subsonic speeds. J. Phy. Soc. Japan 14, 17971810.Google Scholar
Stuart, J. T. 1958 On the nonlinear mechanics of hydrodynamic stability. J. Fluid Mech. 4, 121.Google Scholar
Stuart, J. T. 1962 Nonlinear effects in hydrodynamic stability. In Proc. 10th Int. Congr. Appl. Mech. (ed. F. Rolla & W. T. Koiter), pp. 6397. Elsevier.
Wille, R. 1963 Beiteäge zur Phänomenologie der Freistrahlen. Z. Flugwiss. 11, 222233.Google Scholar
Williams, D. R. & Hama, F. R. 1980 Streaklines in a shear layer perturbed by two waves. Phys. Fluids 23, 442447.Google Scholar
Winant, C. D. & Browand, F. K. 1974 Vortex pairing, the mechanism of turbulent mixing-layer growth at moderate Reynolds number. 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
Wygnanski, I., Oster, D., Fiedler, H. & Dziomba, B. 1979 On the perserverance of a quasitwo-dimensional eddy-structure in a turbulent mixing layer. J. Fluid Mech. 93, 325335.Google Scholar
Zaat, J. A. 1958 In Boundary Layer Research (ed. H. Görtler), p. 127. Springer.
Zhang, Y. Q., Ho, C. M. & Monkewitz, P. 1985 The mixing layer forced by fundamental and subharmonic. In Laminar—Turbulent Transition, IUTAM Symp., Novosibirsk 1984 (ed. V. V. Kozlov), pp. 385395. Springer.