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| Titel |
Modelling of large-scale structures arising under developed turbulent convection in a horizontal fluid layer (with application to the problem of tropical cyclone origination) |
| VerfasserIn |
G. V. Levina, M. V. Starkov, Se. E. Startsev, V. D. Zimin, S. S. Mioseev |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 7, no. 1/2 ; Nr. 7, no. 1/2, S.49-58 |
| Datensatznummer |
250004243
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| Publikation (Nr.) |
 copernicus.org/npg-7-49-2000.pdf |
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| Zusammenfassung |
| The work is concerned with the results of
theoretical and laboratory modelling the processes of the large-scale structure
generation under turbulent convection in the rotating-plane horizontal layer of
an incompressible fluid with unstable stratification. The theoretical model
describes three alternative ways of creating unstable stratification: a layer
heating from below, a volumetric heating of a fluid with internal heat sources
and combination of both factors. The analysis of the model equations show that
under conditions of high intensity of the small-scale convection and low level
of heat loss through the horizontal layer boundaries a long wave instability may
arise. The condition for the existence of an instability and criterion
identifying the threshold of its initiation have been determined. The principle
of action of the discovered instability mechanism has been described.
Theoretical predictions have been verified by a series of experiments on a
laboratory model. The horizontal dimensions of the experimentally-obtained
long-lived vortices are 4÷6 times larger than the thickness of the fluid layer.
This work presents a description of the laboratory setup and experimental
procedure. From the geophysical viewpoint the examined mechanism of the long
wave instability is supposed to be adequate to allow a description of the
initial step in the evolution of such large-scale vortices as tropical cyclones
- a transition form the small-scale cumulus clouds to the state of the
atmosphere involving cloud clusters (the stage of initial tropical
perturbation). |
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