Deformation and breakup mechanisms of single drops during shear

Abstract : The behavior of single drops of isotropic hydroxypropylcellulose solutions immersed in a polydimethylsiloxane matrix subjected to a constant shear rate was investigated using a rheo-optical technique. Our main results concern the nonstationary deformation and breakup mechanisms of drops characterized by large capillary numbers. The deformation of threads follows a pseudoaffine deformation for Ca/Cacrit larger than 2.5 and above a certain strain. The end pinching mechanism occurs at a specific scaled strain, which includes the initial drop size and the applied shear rate. Capillary instabilities develop when the thread diameter reaches a critical value, dr, inversely proportional to the applied shear rate and independent of the initial drop diameter. The time necessary for the total rupture of a thread depends on the initial drop diameter, the applied shear rate, and the critical thread diameter dr. The droplet size resulting from the final rupture of a thread is found to be half that of the critical size, below which a drop deforms into a stable ellipsoid.
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Soumis le : mercredi 9 mars 2011 - 09:55:53
Dernière modification le : lundi 12 novembre 2018 - 10:59:42

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Vassilios Tsakalos, Patrick Navard, Edith Peuvrel-Disdier. Deformation and breakup mechanisms of single drops during shear. Journal of rheology, American Institute of Physics, 1998, 42 (6), pp.Pages 1403-1417. ⟨10.1122/1.550894⟩. ⟨hal-00574910⟩

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