Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-18T21:40:52.506Z Has data issue: false hasContentIssue false

On parametric instabilities of finite-amplitude internal gravity waves

Published online by Cambridge University Press:  20 April 2006

J. Klostermeyer
Affiliation:
Max-Planck-Institut für Aeronomie, 3411 Katlenburg-Lindau, FRG

Abstract

The equations describing parametric instabilities of a finite-amplitude internal gravity wave in an inviscid Boussinesq fluid are studied numerically. By improving the numerical approach, discarding the concept of spurious roots and considering the whole range of directions of the Floquet vector, Mied's work is generalized to its full complexity. In the limit of large disturbance wavenumbers, the unstable disturbances propagate in the directions of the two infinite curve segments of the related resonant-interaction diagram. They can therefore be classified into two families which are characterized by special propagation directions. At high wavenumbers the maximum growth rates converge to limits which do not depend on the direction of the Floquet vector. The limits are different for both families; the disturbance waves propagating at the smaller angle to the basic gravity wave grow at the larger rate.

Type
Research Article
Copyright
© 1982 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

Abramowitz, M. & Stegun, I. A. 1965 Handbook of Mathematical Functions. Dover.
Drazin, P. G. 1977 On the instability of an internal gravity wave. Proc. R. Soc. Lond. A 356, 411–432.
Gill, A. E. 1974 The stability of planetary waves on an infinite beta-plane. Geophys. Fluid Dyn. 6, 2947.Google Scholar
Hasselmann, K. 1967 A criterion for nonlinear wave stability. J. Fluid Mech. 30, 737739.Google Scholar
Klostermeyer, J. 1978 Nonlinear investigation of the spatial resonance effect in the nighttime equatorial F region. J. Geophys. Res. 83, 37533760.Google Scholar
Lorenz, E. N. 1972 Barotropic instability of Rossby wave motion. J. Atmos. Sci. 29, 258264.Google Scholar
Mcewan, A. D. & Robinson, R. M. 1975 Parametric instability of internal gravity waves. J. Fluid Mech. 67, 667687.Google Scholar
Mied, R. P. 1976 The occurrence of parametric instabilities in finite-amplitude internal gravity waves. J. Fluid Mech. 78, 763784.Google Scholar
Mied, R. P. 1978 The instabilities of finite-amplitude barotropic Rossby waves. J. Fluid Mech. 86, 225246.Google Scholar
Phillips, O. M. 1966 Internal wave interactions. In Proc. 6th Symp. Nav. Hyd. (ed. R. D. Cooper & S. W. Doroff), pp. 535544. Office of Naval Research, Dept. Navy, Publ. ARC-136.
Phillips, O. M. 1969 The Dynamics of the Upper Ocean. Cambridge University Press.
Smith, B. T., Boyle, J. M., Dongarra, J. J., Garbow, B. S., Ikebe, Y., Klema, V. C. & Moler, C. B. 1976 Matrix Eigensystem Routines-EISPACK Guide. Springer.