Les gouttes enrobées

Abstract : We created “liquid marbles” which are liquid drops coated with a hydrophobic powder. The powder stays at the surface of the drop and isolates it from the solid substrate which leads to pure non-wetting. We studied the laws of “contact” of such soft marbles on a solid (small liquid marbles are nearly perfectly spherical), and described the dissipation processes associated with their motion. For example, we put the liquid marble in rotation on an inclined plane: at low slope, small viscous drops go faster than bigger ones which show an unusual dissipation process. At large speeds, the drops take remarkable shapes as 2-lobes shape, disks or wheels. We also studied the robustness of these liquid marbles, looking, for example, at their bouncing properties. As an application of this findings, we did (at the lab scale) artificial tektites (stones resulting from the impact of meteorites in earth). We used molten tin to simulate a rotation fluid solidifying with time, and tried to characterise their shapes. We were finally interested in another kind of “non-wetting” by putting an air bubble in a viscous liquid under a slightly inclined plane wetted by the liquid. We found that the viscous dissipation occur mainly near the lubrication film in a zone called “dynamic meniscus” for the biggest drops, which fixes the creeping velocity of these bubbles.
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Fluid Dynamics [physics.flu-dyn]. Université Pierre et Marie Curie - Paris VI, 2002. French


https://tel.archives-ouvertes.fr/tel-00003630
Contributor : Pascale Aussillous <>
Submitted on : Thursday, October 23, 2003 - 5:01:16 PM
Last modification on : Thursday, October 23, 2003 - 5:01:16 PM

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Pascale Aussillous. Les gouttes enrobées. Fluid Dynamics [physics.flu-dyn]. Université Pierre et Marie Curie - Paris VI, 2002. French. <tel-00003630>

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