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Global linear stability of the boundary-layer flow over a rotating sphere

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journal contribution
posted on 25.02.2016, 13:07 by A. Barrow, Stephen John Garrett, N. Peake
We consider the linear global stability of the boundary-layer flow over a rotating sphere. Our results suggest that a self-excited linear global mode can exist when the sphere rotates sufficiently fast, with properties fixed by the flow at latitudes between approximately 55°-65° from the pole (depending on the rotation rate). A neutral curve for global linear instabilities is presented with critical Reynolds number consistent with existing experimentally measured values for the appearance of turbulence. The existence of an unstable linear global mode is in contrast to the literature on the rotating disk, where it is expected that nonlinearity is required to prompt the transition to turbulence. Despite both being susceptible to local absolute instabilities, we conclude that the transition mechanism for the rotating-sphere flow may be different to that for the rotating disk.

History

Citation

European Journal of Mechanics, B/Fluids, 2015, 49 (PB), pp. 301-307

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Mathematics

Version

AM (Accepted Manuscript)

Published in

European Journal of Mechanics

Publisher

Elsevier for European Mechanics Society (Euromech)

issn

0997-7546

Copyright date

2014

Available date

25/02/2016

Publisher version

http://www.sciencedirect.com/science/article/pii/S0997754614000338

Language

en

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