Intermittent direction reversals of moving spatially-localized turbulence observed in two-dimensional Kolmogorov flow
| Autor: | Hiruta, Yoshiki, Toh, Sadayoshi |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | Phys. Rev. E 96, 063112 (2017) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevE.96.063112 |
| Popis: | We have found that in two-dimensional Kolmogorov flow a single spatially-localized turbulence (SLT) exists stably and travels with a constant speed on average switching the moving direction randomly and intermittently for moderate values of control parameters: Reynolds number and the flow rate. We define the coarse-grained position and velocity of an SLT and separate the motion of the SLT from its internal turbulent dynamics by introducing a co-moving frame. The switching process of an SLT represented by the coarse-grained velocity seems to be a random telegraph signal. Focusing on the asymmetry of the internal turbulence we introduce two coarse-grained variables characterizing the internal dynamics. These quantities follow the switching process reasonably. This suggests that the twin attracting invariant sets each of which corresponds to a one-way traveling SLT are embedded in the attractor of the moving SLT and the connection of the two sets is too complicated to be represented by a few degrees of freedom but the motion of an SLT is controlled by the internal turbulent dynamics. Comment: 8pages, 7 figures |
| Databáze: | arXiv |
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