Shear flow energy redistribution stipulated by the internal-gravity wavy structures in the dissipative ionosphere
| Autor: | Oleg Kharshiladze, K.Z. Chargazia, G. D. Aburjania |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Physics
Atmospheric Science 010504 meteorology & atmospheric sciences Turbulence Aerospace Engineering Astronomy and Astrophysics Linear stage Mechanics 01 natural sciences Kármán vortex street 010305 fluids & plasmas Vortex Physics::Fluid Dynamics Nonlinear system Geophysics Amplitude Space and Planetary Science 0103 physical sciences Dissipative system General Earth and Planetary Sciences Shear flow 0105 earth and related environmental sciences |
| Zdroj: | Advances in Space Research. 52:177-191 |
| ISSN: | 0273-1177 |
| DOI: | 10.1016/j.asr.2013.02.011 |
| Popis: | The linear mechanism of generation, intensification and further nonlinear dynamics of internal gravity waves (IGW) in stably stratified dissipative ionosphere with non-uniform zonal wind (shear flow) is studied. In case of the shear flows the operators of linear problem are non-selfadjoint, and the corresponding Eigen functions – nonorthogonal. Thus, canonical – modal approach is of less use studying such motions. Non-modal mathematical analysis becomes more adequate for such problems. On the basis of non-modal approach, the equations of dynamics and the energy transfer of IGW disturbances in the ionosphere with a shear flow is obtained. Exact analytical solutions of the linear as well as the nonlinear dynamic equations of the problem are built. The increment of shear instability of IGW is defined. It is revealed that the transient amplification of IGW disturbances due time does not flow exponentially, but in algebraic – power law manner. The effectiveness of the linear amplification mechanism of IGW at interaction with non-uniform zonal wind is analyzed. It is shown that at initial linear stage of evolution IGW effectively temporarily draws energy from the shear flow significantly increasing (by an order of magnitude) own amplitude and energy. With amplitude growth the nonlinear mechanism turns on and the process ends with self-organization of nonlinear solitary, strongly localized IGW vortex structures (the monopole vortex, the transverse vortex chain or the longitudinal vortex street). Accumulation of these vortices in the ionospheric medium can create the strongly turbulent state. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect