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| Titel |
Unstable periodic motion in turbulent flows |
| VerfasserIn |
G. Kawahara, S. Kida, L. Veen |
| 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 ; 13, no. 5 ; Nr. 13, no. 5 (2006-09-21), S.499-507 |
| Datensatznummer |
250011837
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| Publikation (Nr.) |
 copernicus.org/npg-13-499-2006.pdf |
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| Zusammenfassung |
| Recently found unstable time-periodic solutions
to the incompressible Navier-Stokes equation
are reviewed to discuss their relevance to
plane Couette turbulence and isotropic turbulence.
It is shown that the periodic motion embedded in
the Couette turbulence exhibits
a regeneration cycle of near-wall coherent structures,
which consists of formation and breakdown of
streamwise vortices and low-velocity streaks.
In phase space
a turbulent state wanders around the corresponding periodic orbit
for most of the time, so that
the root-mean-squares of velocity fluctuations of
the Couette turbulence agree very well
with the temporal averages of those along the periodic orbit.
The Kolmogorov universal-range
energy spectrum is observed for the periodic motion
embedded in high-symmetric turbulence
at the Taylor-microscale Reynolds number Reλ=67.
A laminarization strategy inspired by
investigation of the phase-space structure
in the vicinity of the unstable periodic orbit
is presented for the Couette turbulence. |
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