Figures d'impact : tunnels, vases, spirales et bambous

Abstract : We study experimentally different situations of impact of solids onto liquids. We first study the impact at large velocity of a solid sphere in a liquid bath. We observe the sphere's deceleration. We deduce from these laws the force exerted on the sphere by the fluid, and show that a highly sheared foam behaves like a viscous fluid. Such violent impacts also cause air entrapment. We describe the shape of the cavity created in the liquid : tunnel-like in foam, vase-shaped in a viscous oil, it can look like a spiral in water if the projectile is spinning. We then focus on low-velocity impacts on liquid films : soap films or viscous layers spread on solid surfaces. Capillary forces are comparable to the projectiles' inertia. We show that a bead hitting a film can be stucked in the liquid. A foam, containing a large number of such liquid films, can then slow down and trap particles by capillarity.
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Analyse de données, Statistiques et Probabilités [physics.data-an]. Université Pierre et Marie Curie - Paris VI, 2009. Français


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Submitted on : Sunday, June 6, 2010 - 11:30:59 PM
Last modification on : Thursday, September 3, 2015 - 1:10:48 AM
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Anne Le Goff. Figures d'impact : tunnels, vases, spirales et bambous. Analyse de données, Statistiques et Probabilités [physics.data-an]. Université Pierre et Marie Curie - Paris VI, 2009. Français. <tel-00489654>

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