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Instability and transition in finite-amplitude Kelvin–Helmholtz and Holmboe waves

Published online by Cambridge University Press:  26 April 2006

W. D. Smyth
Affiliation:
Department of Physics, University of Toronto, Toronto, Ontario, Canada, M5S 1A7
W. R. Peltier
Affiliation:
Department of Physics, University of Toronto, Toronto, Ontario, Canada, M5S 1A7

Abstract

We investigate the transition to turbulence in a free shear layer which contains a thin central region of stable density stratification. The fluid is assumed to possess Prandtl number significantly larger than unity, and the flow may exhibit either Holmboe or Kelvin–Helmholtz (KH) instability, depending upon the intensity of the stratification. A sequence of two-dimensional nonlinear numerical simulations of flows near the KH–Holmboe transition (i.e. having bulk Richardson numbers near 1/4) clearly illustrates the structural relationship between Holmboe and Kelvin–Helmholtz waves. The time-dependent nonlinear wave states delivered by the simulations are subjected to a three-dimensional normal-mode stability analysis in order to discover the physical processes that might drive the flow towards a turbulent state. Strong secondary instability is found to persist up to large spanwise wavenumbers, with no indication of a preferred lengthscale. These results indicate that secondary instability may lead the flow directly into the turbulent state.

Type
Research Article
Copyright
© 1991 Cambridge University Press

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References

Browand, F. K. & Wang, Y. H. 1972 An experiment on the growth of small disturbances at the interface between two streams of different densities and velocities. Proc. Intl Symp. on Stratified Flows, August 29–31, 1972, Novosibirsk, Soviet Union, pp. 491498.
Browand, F. K. & Winant, C. D. 1973 Laboratory observations of shear instability in a stratified fluid. Boundary-Layer Met. 5, 6777.Google Scholar
Busse, F. 1981 Transition to turbulence in Rayleigh–Bénard convection. In Hydrodynamic Instabilities and the Transition to Turbulence (ed. H. L. Swinney & J. P. Gollub). pp. 97137. Springer.
Clever, R. M. & Busse, F. 1974 Transition to time-dependent convection. J. Fluid Mech. 65, 625645.Google Scholar
Collins, D. A. & Maslowe, S. A. 1988 Vortex pairing and resonant wave interactions in a stratified free shear layer. J. Fluid Mech. 191, 465480.Google Scholar
Di Prima, R. C. & Swinney, H. L. 1981 Instabilities and transition in flow between concentric rotating spheres. In Hydrodynamic Instabilities and the Transition to Turbulence (ed. H. L. Swinney & J. P. Gollub), pp. 139180. Springer.
Hazel, P. 1972 Numerical studies of the stability of inviscid parallel shear flows. J. Fluid Mech. 51, 3962.Google Scholar
Holmboe, J. 1962 On the behaviour of symmetric waves in stratified shear layers. Geofys. Publ. 24, 67113.Google Scholar
Klaassen, G. P. & Peltier, W. R. 1985a The evolution of finite-amplitude Kelvin–Helmholtz billows in two spatial dimensions. J. Atmos. Sci. 42, 13211339.Google Scholar
Klaassen, G. P. & Peltier, W. R. 1985b The onset of turbulence in finite amplitude Kelvin–Helmholtz billows. J. Fluid Mech. 155, 135.Google Scholar
Klaassen, G. P. & Peltier, W. R. 1985c The effect of Prandtl number on the evolution and stability of Kelvin–Helmholtz billows. Geophys. Astrophys. Fluid Dyn. 32, 2360.Google Scholar
Klaassen, G. P. & Peltier, W. R. 1989 The role of transverse secondary instabilities in the evolution of free shear layers. J. Fluid Mech. 202, 367402.Google Scholar
Klaassen, G. P. & Peltier, W. R. 1991 The influence of stratification on secondary instability in free shear layers. J. Fluid Mech. 227, 71106.Google Scholar
Koop, C. G. 1976 Instability and turbulence in a stratified shear layer. PhD thesis, University of Southern California (also published as DDC Rep. ADA 026634).
Koop, C. G. & Browand, F. K. 1979 Instability and turbulence in a stratified fluid with shear. J. Fluid Mech. 93, 135159.Google Scholar
Laprise, R. & Peltier, W. R. 1989 The linear stability of nonlinear mountain waves: Implications for the understanding of severe downslope windstorms. J. Atmos. Sci. 46, 545564.Google Scholar
Lawrence, G. A., Browand, F. K. & Redekopp, L. G. 1990 The stability of a sheared density interface. Phys. Fluids A (in press).Google Scholar
Lawrence, G. A., Lasheras, J. C. & Browand, F. K. 1987 Shear instabilities in stratified flow. Proc. of the Third Intl Symp. on Stratified Flows, February 2–5, 1987, Pasadena, California.
Maxworthy, T. & Browand, F. K. 1975 Experiments in rotating and stratified flows: oceanographic applications. Ann. Rev. Fluid Mech. 7, 273305.Google Scholar
Metcalfe, R. W., Orszag, S. A., Brachet, M. E., Menon, S. & Riley, J. J. 1987 Secondary instability of a temporally growing mixing layer. J. Fluid Mech. 184, 207243.Google Scholar
Nishida, S. & Yoshida, S. 1982 Stability of a two-layer shear flow. Theor. Appl. Mech. 32, 3545.Google Scholar
Orszag, S. A. & Patera, A. 1980 Subcritical transition to turbulence in plane channel flows. Phys. Rev. Lett. 45, 989993.Google Scholar
Pierrehumbert, R. T. 1986 Universal short-wave instability of two-dimensional eddies in an inviscid fluid. Phys. Rev. Lett. 57, 21572159.Google Scholar
Pierrehumbert, R. T. & Widnall, S. E. 1982 The two- and three-dimensional instabilities of a spatially periodic shear layer. J. Fluid Mech. 114, 5982.Google Scholar
Ruelle, D. & Takens, F. 1971 On the nature of turbulence. Commun. Math. Phys. 20, 167192; 23, 343–344.Google Scholar
Smyth, W. D., Klaassen, G. P. & Peltier, W. R. 1988 Finite amplitude Holmboe waves. Geophys. Astrophys. Fluid Dyn. 43, 181222.Google Scholar
Smyth, W. D. & Peltier, W. R. 1989 The transition between Kelvin–Helmholtz and Holmboe instability: An investigation of the overreflection hypothesis. J. Atmos. Sci. 46, 36983720.Google Scholar
Smyth, W. D. & Peltier, W. R. 1990 Three-dimensional primary instabilities of a stratified, dissipative, parallel flow. Geophys. Astrophys. Fluid Dyn. 52, 249261.Google Scholar
Thorpe, S. A. 1968 A method of producing a shear flow in a stratified fluid. J. Fluid Mech. 32, 693704.Google Scholar
Thorpe, S. A. 1985 Laboratory observations of secondary structures in Kelvin–Helmholtz billows and consequences for ocean mixing. Geophys. Astrophys. Fluid Dyn. 34, 175199.Google Scholar
Thorpe, S. A. 1987 Transition phenomena and the development of turbulence in stratified fluids. J. Geophys. Res. 92, 52315248.Google Scholar
Yoshida, S. 1977 On a mechanism for breaking interfacial waves. Coastal Engng Japan 20, 715.Google Scholar