Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-18T18:40:30.017Z Has data issue: false hasContentIssue false

Existence and stability of stationary vortices in a uniform shear flow

Published online by Cambridge University Press:  26 April 2006

J. Nycander
Affiliation:
Department of Technology, Uppsala University, Box 534, 751 21 Uppsala, Sweden

Abstract

Isolated vortices in a background flow of constant shear are studied. The flow is governed by the two-dimensional Euler equation. An infinite family of integral invariants, the Casimirs, constrain the flow to an isovortical surface. An isovortical surface consists of all flows that can be obtained by some incompressible deformation of a given vorticity field. It is proved that on every isovortical surface satisfying appropriate conditions there exists a stationary solution, stable to all exponentially growing disturbances, which represents a localized vortex that is elongated in the direction of the external flow. The most important condition is that the vorticity anomaly q in the vortex has the same sign as the external shear. The validity of the proof also requires that q is non-zero only in a finite region, and that 0 < qminqqmax ≤ ∞ in this region (assuming the external shear to be positive).

Type
Research Article
Copyright
© 1995 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Antipov, S. V., Nezlin, M. V., Snezhkin, E. N. & Trubnikov, A. S. 1985 Rossby autosoliton and laboratory model of Jupiter's Great Red Spot. Sov. Phys. JETP 62, 10971107.Google Scholar
Bandle, C. 1980 Isoperimetric Inequalities and Applications. Pitman.
Benjamin, T. B. 1976 The alliance of practical and analytical insights into the nonlinear problems of fluid mechanics. In Applications of Methods of Functional Analysis to Problems in Mechanics. Lecture Notes in Mathematics, vol. 503 (ed. A. Dold & B. E Ckman), pp. 829. Springer.
Burton, G. R. 1988 Steady symmetric vortex pairs and rearrangements. Proc. R. Soc. Edinb. A 108, 269290.Google Scholar
Carnevale, G. F. & Vallis, G. K. 1990 Pseudo-advective relaxation to stable states of inviscid two-dimensional fluids. J. Fluid Mech. 213, 549571.Google Scholar
Deem, G. S. & Zabusky, N. J. 1978 Vortex waves: stationary ‘V states’, interactions, recurrence, and breaking. Phys. Rev. Lett. 40, 859862.Google Scholar
Filippov, D. V. & Yan'kov, V. V 1986 Two-dimensional electron vortices. Fiz. Plazmy 12, 953960 (English transl. Sov. J. Plasma Phys. 12, 548–552).Google Scholar
Hardy, G. H., Littlewood, J. E. & Polya, G. 1952 Inequalities, 2nd edn. Cambridge University Press.
Kida, S. 1981 Motion of an elliptic vortex in a uniform shear flow. J. Phys. Soc. Japan 50, 35173520.Google Scholar
Legras, B. & Dritschel, D. G. 1993 A comparison of the contour surgery and pseudo-spectral methods. J. Comput. Phys. 104, 287302.Google Scholar
Marcus, P. S. 1990 Vortex dynamics in a shearing zonal flow. J. Fluid Mech. 215, 393430.Google Scholar
McIntyre, M. E. & Shepherd, T. G. 1987 An exact local conservation theorem for finite-amplitude disturbances to non-parallel shear flows, with remarks on Hamiltonian structure and on Arnol'd's stability theorems. J. Fluid Mech. 181, 527565.Google Scholar
Moore, D. W. & Saffman, P. G. 1971 Structure of a line vortex in an imposed strain. In Aircraft Wake Turbulence and its Detection (ed. J. H. Olsen, A. Goldburg & M. Rogers), pp. 339354. Plenum.
Morrison, P. J. & Kotschenreuther, M. 1990 The free energy principle, negative energy modes, and stability. In Nonlinear World: IV International Workshop on Nonlinear and Turbulent Processes in Physics, Kiev, USSR, 1989 (ed. V. G. Bar'yakhtar, V. M. Chernousenko, N. S. Erokhin, A. G. Sitenko & V. E. Zakharov), pp. 910932. World Scientific.
Morrison, P. J. & Pfirsch, D. 1989 Free energy expressions for Vlasov equilibria. Phys. Rev. A 40, 38983910.Google Scholar
Nycander, J. 1994 Steady vortices in plasmas and geophysical flows. Chaos 4, 253267.Google Scholar
Petviashvili, V. I. & Yan'kov, V. V. 1984 Solitons and turbulence. In Voprosy Teorii Plazmy, vol. 14 (ed. B. B. Kadomtsev). Energoatomizdat (English transl.: Reviews of Plasma Physics, vol. 14, 1989, pp. 1–62. Consultants Bureau).
Sobolev, S. L. 1963 On a theorem of functional analysis. Am. Math. Soc. Transl. 34 (2), 3968.Google Scholar
Sommeria, J., Meyers, S. D. & Swinney, H. L. 1988 Laboratory simulation of Jupiter's great red spot. Nature 331, 689693.Google Scholar
Toh, S., Ohkitani, K. & Yamada, M. 1991 Enstrophy and momentum fluxes in two-dimensional shear flow turbulence. Physica D 51, 569578.Google Scholar
Ziemer, W. P. 1989 Weakly Differentiable Functions. Graduate texts in mathematics, vol. 120. Springer.