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Hamiltonian dynamics of internal waves

Published online by Cambridge University Press:  20 April 2006

D. Michael Milder
Affiliation:
Aretê Associates, P.O. Box 350, Encino, CA 91316, U.S.A.

Abstract

The isopycnal elevation ζ of a stratified incompressible fluid constitutes a generalized co-ordinate in terms of which the dynamics can be described in Hamiltonian form. The description is complete, and no additional variables are necessary, when the isopycnal circulation vanishes and when there are no remote sources of flow. The Hamiltonian, constructed in a co-ordinate system that coincides with the isopycnal surfaces, generates nonlinear equations of motion for ζ and its conjugate variable π which are formally exact for arbitrary displacements of the fluid and which are equivalent at lowest order to the usual linearized equations of internal waves. The appropriate scaling parameters for the nonlinearity are the isopycnal slope [dtri ]ζ and vertical strain ∂zζ, which emerge as the expansion parameters of an explicit powerseries representation of the Hamiltonian.

Type
Research Article
Copyright
© 1982 Cambridge University Press

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References

Bretherton, F. P. & Garret, C. J. R. 1969 Proc. R. Soc. Lond. A 302, 529.
Bretherton, F. P. 1970 A note on Hamilton's principle for perfect fluids. J. Fluid Mech. 44, 19.Google Scholar
Henyey, F. S. 1981 Hamiltonian description of stratified fluid dynamics. La Jolla Institute Rep. LJI-R-81–162 (to be published.)Google Scholar
Hill, E. L. 1951 Hamilton's principle and the conservation theorems of mathematical physics. Rev. Mod. Phys. 23, 253.Google Scholar
Lanczos, C. 1966 The Variational Principles of Mechanics. University of Toronto Press.
Meiss, J. D., Pomphrey, N. & Watson, K. M. 1979 Numerical analysis of weakly nonlinear wave turbulence. Proc. Nat. Acad. Sci. U.S.A. 76, 2109.Google Scholar
Miles, J. W. 1981 Hamiltonian formulations for surface waves. Appl. Sci. Res. 37, 103.Google Scholar