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Titel |
The evolution of a thermocline effected by a turbulent stream |
VerfasserIn |
O. A. Druzhinin, V. I. Kazakov, P. A. Matusov, L. A. Ostrovsky |
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 ; 2, no. 1 ; Nr. 2, no. 1, S.49-57 |
Datensatznummer |
250000365
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Publikation (Nr.) |
copernicus.org/npg-2-49-1995.pdf |
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Zusammenfassung |
The process of thermocline evolution under the action of turbulent stream in the
upper layer is investigated in laboratory experiment in thermally stratified tank, the
initial temperature profile with pronounced thermocline being similar to that observed in
tropic seas. The mean velocity and turbulent energy spatial distributions have been shaped
to model the hydrological conditions in strong oceanic currents or wind-induced drag
currents.
The experiment demonstrates the gradual deepening and transformation of thermocline in a
case where no global instability took place (i.e., with Richardson numbers always
exceeding 0.3-0.4). The process of thermocline evolution resulted also in recurring
"bursts" of microstructure.
A numerical experiment based on equations of semi-empirical theory of turbulence shows
quantitative agreement with experimental data. Moreover, simple analytical solutions and
numerical results show that a layer with marginal stability is formed with Richardson
numbers being very close to the stability threshold, so that quite small disturbances in
thermocline can result in appearance of internal waves and bursts of turbulence. |
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