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Nonlinear Kelvin–Helmholtz instability of a finite vortex layer

Published online by Cambridge University Press:  20 April 2006

C. Pozrikidis
Affiliation:
Department of Chemical Engineering, University of Illinois. 1209 W California Street, Urbana, Illinois 61801
J. J. L. Higdon
Affiliation:
Department of Chemical Engineering, University of Illinois. 1209 W California Street, Urbana, Illinois 61801

Abstract

The nonlinear growth of periodic disturbances on a finite vortex layer is examined. Under the assumption of constant vorticity, the evolution of the layer may be analysed by following the contour of the vortex region. A numerical procedure is introduced which leads to higher-order accuracy than previous methods with negligible increase in computational effort. The response of the vortex layer is studied as a function of layer thickness and the amplitude and form of the initial disturbance. For small initial disturbances, all unstable layers form a large rotating vortex core of nearly elliptical shape. The growth rate of the disturbances is strongly affected by the layer thickness; however, the final amplitude of the disturbance is relatively insensitive to the thickness and reaches a maximum value of approximately 20% of the wavelength. In the fully developed layers, the amplitude shows a small oscillation owing to the rotation of the vortex core. For finite-amplitude initial disturbances, the evolution of the layer is a function of the initial amplitude. For thin layers with thickness less than 3% of the wavelength, three different patterns were observed in the vortex-core region: a compact elliptic core, an elongated S-shaped core and a bifurcation into two orbiting cores. For thicker layers, stationary elliptic cores may develop if the thickness exceeds 15% of the wavelength. The spacing and eccentricity of these cores is in good agreement with previously discovered steady-state solutions. The growth rate of interfacial area (or length of the vortex contour) is calculated and is found to approach a constant value in well-developed vortex layers.

Type
Research Article
Copyright
© 1985 Cambridge University Press

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References

Acton E.1976 The modelling of large eddies in a two-dimensional shear layer. J. Fluid Mech. 76, 561592.Google Scholar
Aref H.1983 Integrable, chaotic and turbulent vortex motion in two-dimensional flows. Ann. Rev. Fluid Mech. 15, 345389.Google Scholar
Aref, H. & Siggia E. D.1980 Vortex dynamics of the two dimensional turbulent shear layer. J. Fluid Mech. 100, 705737.Google Scholar
Ashurst W. T.1979 Numerical simulation of turbulent mixing layers via vortex dynamics. In Turbulent Shear Flows 1 (ed. F. Durst et al.), pp. 402413. Springer.
Birkhoff G.1962 Helmholtz and Taylor instability. Proc. Symp. Appl. Math. Am. Math. Soc. 13, 5576.Google Scholar
Breidenthal R.1981 Structure in turbulent mixing layers and wakes using a chemical reaction. J. Fluid Mech. 109, 124.Google Scholar
Corcos, G. M. & Sherman F. S.1976 Vorticity concentration and the dynamics of unstable shear layers. J. Fluid Mech. 73, 241264.Google Scholar
Corcos, G. M. & Sherman F. S.1984 The mixing layer: deterministic models of a turbulent flow. Part 1. Introduction and the two-dimensional flow. J. Fluid Mech. 139, 2965.Google Scholar
Deem, S. G. & Zabusky N. J.1978 Vortex waves: stationary ‘V states’, interactions, recurrence and breaking. Phys. Rev. Lett. 40, 859862.Google Scholar
Gear C. W.1971 Numerical Initial Value Problems in Ordinary Differential Equations. Prentice Hall.
Higdon, J. J. L. & Pozrikidis, C. 1985 The self-induced motion of vortex sheets. J. Fluid Mech. 150, 203231.Google Scholar
Ho, C. M. & Huerre P.1984 Perturbed free shear layers. Ann. Rev. Fluid Mech. 16, 365424.Google Scholar
Kirchhoff G. R.1876 Mechanik. Leipzig: B. G. Teubner.
Krasny R.1984 Ph.D. dissertation. University of California, Berkeley.
Lamb H.1932 Hydrodynamics. Dover.
Love A. E. H.1894 On the stability of certain vortex motions. Proc. Lond. Math. Soc. Ser. 1 25, 1843.Google Scholar
Meiron D. I., Baker, G. R. & Orszag S. A.1982 Analytical structure of vortex sheet dynamics. Part 1. Kelvin—Helmholtz instability. J. Fluid Mech. 114, 283298.Google Scholar
Overman, E. A. & Zabusky N. J.1982 Evolution and merger of isolated vortex structures. Phys. Fluids 25, 12971305.Google Scholar
Pierrehumbert, R. T. & Widnall S. E.1981 The structure of organized vortices in a free shear layer. J. Fluid Mech. 102, 301313.Google Scholar
Pullin D. I.1981 The nonlinear behaviour of a constant vorticity layer at a wall. J. Fluid Mech. 108, 401421.Google Scholar
Rayleigh Lord1980 On the stability or instability of certain fluid motions. Proc. Lond. Math. Soc. xi, 5770.Google Scholar
Saffman, P. G. & Szeto R.1980 Equilibrium shapes of a pair of equal uniform vortices. Phys. Fluids 23, 23392342.Google Scholar
Saffman, P. G. & Szeto R.1981 Structure of a linear array of uniform vortices. Stud. Appl. Math. 65, 223248.Google Scholar
Zabusky N. J., Hughes, M. H. & Roberts K. V.1979 Contour dynamics for the Euler equations in two dimensions. J. Comp. Phys. 30, 96106.Google Scholar