scholarly journals Internal-Gravity-Wave Interactions in the Presence of Localized Chemical Heating in the Atmosphere

2019 ◽  
Author(s):  
Ahmed Almohaimeed
Keyword(s):  
Gravity Wave ◽  
Internal Gravity Wave ◽  
Wave Interactions ◽  
Chemical Heating

On the instability of an internal gravity wave

1977 ◽  
Vol 356 (1686) ◽  
pp. 411-432 ◽  
Keyword(s):  
Gravity Wave ◽  
Parametric Instability ◽  
Normal Modes ◽  
Internal Gravity Wave ◽  
Marginal Stability ◽  
Wave Interactions ◽  
Resonant Wave ◽  
Physical Conclusion ◽  
Arbitrary Amplitude ◽  
Boussinesq Fluid

The linear stability of an internal gravity wave of arbitrary amplitude in an unbounded stratified inviscid Boussinesq fluid is considered mathematically. The instability is shown to be governed by a Floquet system and treated by a generalization of the method of normal modes. Some properties of the Floquet system, and in particular those of its parametric instability, are analysed. The parametric instability is related to the theory of resonant wave interactions; and the surface of marginal stability in the control space of the amplitude and wavenumbers is shown to be describable by the catastrophe theory of Thom. Finally some results of numerical calculations of the marginal surface are shown. The main physical conclusion is to confirm that the internal gravity wave is unstable always, even when its amplitude is small and so its local Richardson number is large everywhere for all time. It is suggested, by various illustrations and arguments, that the methods developed in this paper are applicable to the instability of many symmetric nonlinear waves.

On parametric instabilities of finite-amplitude internal gravity waves

1982 ◽  
Vol 119 ◽  
pp. 367-377 ◽  
Author(s):  
J. Klostermeyer
Keyword(s):  
Gravity Wave ◽  
Internal Gravity Wave ◽  
Maximum Growth ◽  
Numerical Approach ◽  
Internal Gravity Waves ◽  
Resonant Interaction ◽  
Finite Amplitude ◽  
Interaction Diagram ◽  
Parametric Instabilities ◽  
Boussinesq Fluid

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.

scholarly journals Numerical Evaluation of Energy Transfers in Internal Gravity Wave Spectra of the Ocean

2019 ◽  
Vol 49 (3) ◽  
pp. 737-749 ◽  
Author(s):  
Carsten Eden ◽  
Friederike Pollmann ◽  
Dirk Olbers
Keyword(s):  
Fine Structure ◽  
Gravity Wave ◽  
Numerical Evaluation ◽  
Weak Interactions ◽  
Wave Spectrum ◽  
Internal Gravity Wave ◽  
Spectral Energy ◽  
Spectral Slope ◽  
Energy Transfers ◽  
Mixing Rates

AbstractSpectral energy transfers by internal gravity wave–wave interactions for given empirical energy spectra are evaluated numerically from the kinetic equation that is derived from the assumption of weak interactions. Wave spectrum parameters, such as bandwidth, spectral slope, and Coriolis frequency f, are varied, as is the spectral resolution. In agreement with previous studies, we find in all cases a forward energy cascade toward smaller vertical and horizontal wavelengths. Energy sinks due to the transfers are predominantly at frequencies between 2f and 3f. While the mechanism of the energy transfer differs partly from findings of previous studies, a parameterization for internal wave dissipation—which is used in the fine structure parameterization to estimate dissipation and mixing rates from observations—agrees well with the numerical evaluation of the energy transfers. We also find a dependency of the energy transfers on the spectral slope, offering the possibility to decrease the bias of the fine structure parameterization by improving the knowledge about the spatial variations of this (and other) spectral parameter.

Particle drift in the field of internal gravity wave

2000 ◽  
Vol 26 (8) ◽  
pp. 1305-1324 ◽  
Author(s):  
S.A. Grinshpun ◽  
Yu.N. Redcoborody ◽  
S.G. Kravchuk ◽  
V.I. Zadorozhnii ◽  
V.I. Zhdanov
Keyword(s):  
Gravity Wave ◽  
Internal Gravity Wave ◽  
Particle Drift
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