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On the evolution of a wave packet in a laminar boundary layer

Published online by Cambridge University Press:  26 April 2006

Jacob Cohen
Affiliation:
Faculty of Aerospace Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel
Kenneth S. Breuer
Affiliation:
Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Joseph H. Haritonidis
Affiliation:
Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

Abstract

The transition process of a small-amplitude wave packet, generated by a controlled short-duration air pulse, to the formation of a turbulent spot is traced experimentally in a laminar boundary layer. The vertical and spanwise structures of the flow field are mapped at several downstream locations. The measurements, which include all three velocity components, show three stages of transition. In the first stage, the wave packet can be treated as a superposition of two- and three-dimensional waves according to linear stability theory, and most of the energy is centred around a mode corresponding to the most amplified wave. In the second stage, most of the energy is transferred to oblique waves which are centred around a wave having half the frequency of the most amplified linear mode. During this stage, the amplitude of the wave packet increases from 0.5 % to 5 % of the free-stream velocity. In the final stage, a turbulent spot develops and the amplitude of the disturbance increases to 27 % of the free-stream velocity.

Theoretical aspects of the various stages are considered. The amplitude and phase distributions of various modes of all three velocity components are compared with the solutions provided by linear stability theory. The agreement between the theoretical and measured distributions is very good during the first two stages of transition. Based on linear stability theory, it is shown that the two-dimensional mode of the streamwise velocity component is not necessarily the most energetic wave. While linear stability theory fails to predict the generation of the oblique waves in the second stage of transition, it is demonstrated that this stage appears to be governed by Craik-type subharmonic resonances.

Type
Research Article
Copyright
© 1991 Cambridge University Press

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References

Amini, J. & Lespinard, G., 1982 Experimental study of an “incipient spot” in a transitional boundary layer. Phys. Fluids 25, 17431750.Google Scholar
Bayly, B. J., Orszag, S. A. & Herbert, T., 1988 Instability mechanisms in shear-flow transition. Ann. Rev. Fluid Mech. 20, 359391.Google Scholar
Benjamin, T. B.: 1961 The development of three-dimensional disturbances in an unstable film of liquid flowing down an inclined plane. J. Fluid Mech. 10, 401419.Google Scholar
Benney, D. J. & Gustavsson, L. H., 1981 A new mechanism for linear and nonlinear hydrodynamic instability. Stud. Appl. Maths 64, 185209.Google Scholar
Benney, D. J. & Lin, C. C., 1960 On the secondary motion induced by oscillations in a shear flow. Phys. Fluids 3, 656657.Google Scholar
Breuer, K. S. & Haritonidis, J. H., 1990 The evolution of a localized disturbance in a laminar boundary layer. Part 1. Weak disturbances. J. Fluid Mech. 220, 569594.Google Scholar
Breueb, K. S. & Landahl, M. T., 1990 The evolution of a localized disturbance in a laminar boundary layer. Part 2. Strong disturbances. J. Fluid Mech. 220, 595621.Google Scholar
Conte, S. D.: 1966 The numerical solution of linear boundary layer problems. Stud. Appl. Maths 8, 309321.Google Scholar
Corke, T. C. & Mangano, R. A., 1989 Resonant growth of three-dimensional modes in transitional Blasius boundary layers. J. Fluid Mech. 209, 93150.Google Scholar
Craik, A. D. D.: 1971 Nonlinear resonant instability in boundary layers. J. Fluid Mech. 50, 393413.Google Scholar
Craik, A. D. D.: 1981 The development of wavepackets in unstable flows. Proc. R. Soc. Lond. A 373, 457476.Google Scholar
Craik, A. D. D.: 1985 Wave Interactions and Fluid Flows. Cambridge University Press.
Criminale, W. O. & Kovasznay, L. S. G. 1962 The growth of localized disturbances in alaminar boundary layer. J. Fluid Mech. 14, 5980.Google Scholar
Davey, A. & Reid, W. H., 1977 On the stability of stratified viscous plane Couette flow. J. Fluid Mech. 80, 509.Google Scholar
Gaster, M.: 1968 The development of three-dimensional wave packets in a boundary layer. J. Fluid Mech. 32, 173184.Google Scholar
Gaster, M.: 1975 A theoretical model for the development of a wave packet in a laminar boundary layer. Proc. R. Soc. Lond. A 347, 271289.Google Scholar
Gaster, M.: 1982a Estimates of the error incurred in various asymptotic representations of wave packets. J. Fluid Mech. 121, 365377.Google Scholar
Gaster, M.: 1982b The development of a two-dimensional wavepacket in a growing boundary layer. Proc. R. Soc. Lond. A 384, 317332.Google Scholar
Gaster, M. & Grant, I., 1975 An experimental investigation of the formation and development of a wave packet in a laminar boundary layer. Proc. R. Soc. Lond. A 347, 253269.Google Scholar
Gustavsson, L. H.: 1978 On the evolution of disturbances in boundary layer flows. Royal Institute of Technology, Department of Mechanics Rep. Trita-Mek-78–02.Google Scholar
Henningson, D. S.: 1988 The inviscid initial value problem for a piecewise linear mean flow. Stud. Appl. Maths 78, 3156.Google Scholar
Herbert, T.: 1984 Analysis of the subharmonic route to transition in boundary layers. AIAA Paper 84–0009.Google Scholar
Herbert, T.: 1988 Secondary instability of boundary layers. Ann. Rev. Fluid Mech. 20, 487526.Google Scholar
Itoh, N.: 1984 Landau coefficients of the Blasius boundary-layer flow. In Turbulence and Chaotic Phenomena in Fluids (ed. T. Tatsumi), p. 59. North-Holland.
Itoh, N.: 1987 Another route to the three-dimensional development of Tollmien-Schlichting waves with finite amplitude. J. Fluid Mech. 181, 116.Google Scholar
Jordinson, R.: 1970 The flat plate boundary layer. Part 1. Numerical integration of the Orr-Sommerfeld equation. J. Fluid Mech. 43, 801811.Google Scholar
Kachanov, Y. S. & Levchenko, V. Y., 1984 The resonant interaction of disturbances at laminar turbulent transition in a boundary layer. J. Fluid Mech. 138, 209247.Google Scholar
Klebanoff, P. S., Tidstrom, K. D. & Sargent, L. M., 1962 The three dimensional nature of boundary layer instability. J. Fluid Mech. 12, 134.Google Scholar
Landahl, M. T.: 1975 Wave breakdown and turbulence. SIAM J. Appl. Maths 28, 735756.Google Scholar
Landahl, M. T.: 1980 A note on an algebraic instability of inviscid parallel shear flows. J. Fluid Mech. 98, 243251.Google Scholar
Morkovin, M. V.: 1969 The many faces of transition. In Viscous Drag Reduction (ed. C. Wells). Plenum.
Raetz, G. S.: 1959 A new theory of the cause of transition in fluid flows. Norair Rep. NOR-59–383. Hawthorne, CA.Google Scholar
Raetz, G. S.: 1964 Current status of resonance theory of transition. Norair Rep. NOR-64–111. Hawthorne, CA.Google Scholar
Saric, W. S. & Thomas, A. S. W. 1984 Experiments on the subharmonic route to turbulence in boundary layers. In Turbulence and Chaotic, Phenomena in Fluids (ed. T. Tatsumi), p. 117. North-Holland.
Schlichting, H.: 1933 Zur Entstehung de Turbulenz bei der Plattenströmung plattenstromung. Nachr. Ges. Wiss. Göttingen, 182–208.Google Scholar
Schubauer, G. B. & Skramstad, H. K., 1947 Laminar boundary layer oscillations and stability of laminar flow. J. Aero. Sci. 14, 6978.Google Scholar
Squie, H. B.: 1933 On the stability for three-dimensional disturbances of viscous flow between parallel walls. Proc. R. Soc. Lond. A 142, 621628.Google Scholar
Stuart, J. T.: 1962 On three-dimensional non-linear effects in the stability of parallel flows. Adv. Aero. Sci. 3, 121142.Google Scholar
Stuartson, K. & Stuart, J. T., 1971 A non-linear instability theory of a wave system in plane Poiseuille flow. J. Fluid Mech. 48, 529545.Google Scholar
Tollmien, W.: 1929 Über die Entstehung der Turbulenz. Nachr. Ges. Wiss. Göttingen, 2144 (transl. NACA TM 609).Google Scholar
Watson, J.: 1960 Three-dimensional disturbances in flow between parallel planes. Proc. R. Soc. Land. A 254, 562569.Google Scholar