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| Titel |
Instability patterns between counter-rotating disks |
| VerfasserIn |
F. Moisy, T. Pasutto, M. Rabaud |
| 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 ; 10, no. 3 ; Nr. 10, no. 3, S.281-288 |
| Datensatznummer |
250007997
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| Publikation (Nr.) |
 copernicus.org/npg-10-281-2003.pdf |
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| Zusammenfassung |
| The instability
patterns in the flow between counter-rotating disks (radius to height
ratio R/h from 3.8 to 20.9) are investigated experimentally by
means of visualization and Particle Image Velocimetry. We restrict
ourselves to the situation where the boundary layers remain stable,
focusing on the shear layer instability that occurs only in the
counter-rotating regime. The associated pattern is a combination of a
circular chain of vortices, as observed by Lopez et al. (2002) at low
aspect ratio, surrounded by a set of spiral arms, first described by
Gauthier et al. (2002) in the case of high aspect ratio. Stability curve
and critical modes are measured for the whole range of aspect ratios. From
the measurement of a local Reynolds number based on the shear layer
thickness, evidence is given that a free shear layer instability, with
only weak curvature effect, is responsible for the observed patterns.
Accordingly, the number of vortices is shown to scale as the shear layer
radius, which results from the competition between the centrifugal effects
of each disk. |
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