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| Titel |
The lifecycle of axisymmetric internal solitary waves |
| VerfasserIn |
J. M. McMillan, B. R. Sutherland |
| 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 ; 17, no. 5 ; Nr. 17, no. 5 (2010-09-10), S.443-453 |
| Datensatznummer |
250013724
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| Publikation (Nr.) |
 copernicus.org/npg-17-443-2010.pdf |
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| Zusammenfassung |
| The generation and evolution of solitary waves by intrusive gravity currents
in an approximate two-layer fluid with equal upper- and lower-layer depths is
examined in a cylindrical geometry by way of theory and numerical
simulations. The study is limited to vertically symmetric cases in which the
density of the intruding fluid is equal to the average density of the
ambient. We show that even though the head height of the intrusion decreases,
it propagates at a constant speed well beyond 3 lock radii. This is because
the strong stratification at the interface supports the formation of a mode-2
solitary wave that surrounds the intrusion head and carries it outwards at a
constant speed. The wave and intrusion propagate faster than a linear long
wave; therefore, there is strong supporting evidence that the wave is indeed
nonlinear. Rectilinear Korteweg-de Vries theory is extended to allow the wave
amplitude to decay as r-p with p=½ and the theory is
compared to the observed waves to demonstrate that the width of the wave
scales with its amplitude. After propagating beyond 7 lock radii the
intrusion runs out of fluid. Thereafter, the wave continues to spread
radially at a constant speed, however, the amplitude decreases sufficiently
so that linear dispersion dominates and the amplitude decays with distance as
r-1. |
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