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Non-linear shape oscillations of rising drops and bubbles: Experiments and simulations

Lalanne, Benjamin and Abi Chebel, Nicolas and Vejražka, Jiří and Tanguy, Sébastien and Masbernat, Olivier and Risso, Frédéric Non-linear shape oscillations of rising drops and bubbles: Experiments and simulations. (2015) Physics of Fluids, vol.27 (n°12). pp.123305-1-123305-16. ISSN 1070-6631

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Official URL: http://dx.doi.org/10.1063/1.4936980

Abstract

This paper focuses on shape-oscillations of a gas bubble or a liquid drop rising in another liquid. The bubble/drop is initially attached to a capillary and is released by a sudden motion of that capillary, resulting in the rise of the bubble/drop along with the oscillations of its shape. Such experimental conditions make difficult the interpretation of the oscillation dynamics with regard to the standard linear theory of oscillation because (i) amplitude of deformation is large enough to induce nonlinearities, (ii) the rising motion may be coupled with the oscillation dynamics, and (iii) clean conditions without residual surfactants may not be achieved. These differences with the theory are addressed by comparing experimental observation with numerical simulation. Simulations are carried out using Level-Set and Ghost-Fluid methods with clean interfaces. The effect of the rising motion is investigated by performing simulations under different gravity conditions. Using a decomposition of the bubble/drop shape into a series of spherical harmonics, experimental and numerical time evolutions of their amplitudes are compared. Due to large oscillation amplitude, non-linear couplings between the modes are evidenced from both experimental and numerical signals; modes of lower frequency influence modes of higher frequency, whereas the reverse is not observed. Nevertheless, the dominant frequency and overall damping rate of the first five modes are in good agreement with the linear theory. Effect of the rising motion on the oscillations is globally negligible, provided the mean shape of the oscillation remains close to a sphere. In the drop case, despite the residual interface contamination evidenced by a reduction in the terminal velocity, the oscillation dynamics is shown to be unaltered compared to that of a clean drop.

Item Type:Article
Additional Information:Thanks to American Institute of Physics editor. The definitive version is available at http://scitation.aip.org/;jsessionid=6kf38qr3nk0bj.x-aip-live-06 The original PDF of the article can be found at AIP Scitation website : http://scitation.aip.org/content/aip/journal/pof2/27/12/10.1063/1.4936980
HAL Id:hal-01308141
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Academy of Sciences (CZECH REPUBLIC)
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 Paul Sabatier-Toulouse III - UPS (FRANCE)
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Deposited By: Benjamin LALANNE
Deposited On:04 Jan 2016 12:55

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