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Linear instability of the path of a freely rising spheroidal bubble

Tchoufag, Joël and Magnaudet, Jacques and Fabre, David Linear instability of the path of a freely rising spheroidal bubble. (2014) Journal of Fluid Mechanics, 751 (R4). 1-12. ISSN 0022-1120

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Official URL: http://dx.doi.org/10.1017/jfm.2014.340

Abstract

Path and wake instabilities of buoyancy-driven oblate spheroidal bubbles with a prescribed shape rising freely in a viscous fluid otherwise at rest are studied using global stability analysis, following the technique recently developed for a coupled fluid + body system by Tchoufag, Fabre & Magnaudet (J. Fluid Mech. vol. 740, 2014, pp. 278–311). The essential role of the wake on the path instability is evidenced by comparing the shape of the global stability diagram with that obtained in the case of a fixed bubble. However, dramatic differences are also found, since the critical curve of the coupled system mostly involves low- and high-frequency oscillating modes, whereas that of a fixed bubble only involves stationary modes. Comparison of the present predictions with results obtained through direct numerical simulation is achieved in several regimes, confirming the predictions of the linear approach but also highlighting some of its limitations when the system successively encounters several unstable modes.

Item Type:Article
Additional Information:Thanks to Cambridge University Press (CUP) editor. The definitive version is available at http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9289995&fileId=S0022112014003401
HAL Id:hal-01015463
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
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Deposited By: Jacques MAGNAUDET
Deposited On:26 Jun 2014 13:26

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