Quelques problèmes de dynamique d'interfaces molles

Abstract : This theoretical work presents four topics of research which deal with the dynamics of various soft interfaces. (1) Drops and films over a porous substrate: We studied the deformation of a drop under the combined action of liquid suction and contact line pinning on the substrate. We also considered the situation of a film entrained on a porous plate withdrawn from a pool: the film has a finite height, which we computed, and presents a non-trivial structure in the vicinity of the contact line. (2) Interdiffusion and cross-linking at polymer interfaces: The formation of a strong joint between two polymeric pieces requires that a good amount of chain interdiffusion is attained. This process is however hindered by the introduction of a cross-linker (added to reinforce the bulk of the material). We modeled the competition that thus takes place, and we were able to extract a simple parameter controlling the final state of the system and to give predictions for the adhesion strength in two limiting regimes. (3) Granular flows: We computed a complete analytical description of an avalanche on a sandpile, when the flow displays a linear velocity profile. Among the predictions, it was found that the maximum thickness reached in the avalanche is proportional to the square root of the pile extension. (4) Dynamics of vertical soap films: The recent theories explaining the drainage of these films are based on hydrodynamic instabilities ("marginal regeneration"). We tried to precisely determine their precursor state: in a generic fashion, the film forms a pinched region, whose dimensions were derived analytically; this region may gather the features required for the emergence of the instabilities.
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Contributor : Achod André Aradian <>
Submitted on : Friday, June 7, 2002 - 4:37:56 PM
Last modification on : Thursday, February 7, 2019 - 1:33:34 AM
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  • HAL Id : tel-00001386, version 1


Achod André Aradian. Quelques problèmes de dynamique d'interfaces molles. Dynamique des Fluides [physics.flu-dyn]. Université Pierre et Marie Curie - Paris VI, 2001. Français. ⟨tel-00001386⟩



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