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Theses

Etude de l'Interaction Polymère-Ecoulement

Abstract : Minute amounts of a high molecular weight flexible polymer lead to drastic changes in the flow properties of liquids. This thesis presents a detailed experimental study of the Polymer - Flow Interaction in two idealized situations : When a drop of fluid detaches from a capillary, singular behavior ensues. Very small amounts of polymer inhibit this singularity in an abrupt way and give rise, after a period of self-similar dynamics as for simple liquids, to longlived cylindrical necks or filaments which thin exponentially in time. This abrupt change occurs when the elongation rates become comparable to the inverse of the polymer relaxation time leading to a large elongational viscosity of the dilute polymer solution. Polymers affect two dimensional turbulence, generated in rapidly flowing soap films, in unexpected ways. Their presence inhibits the transfers of energy to large scales, causing their suppression in the energy density spectrum, through a reduction of large elongation rates. This also leads to the change of the spectral properties of a passive scalar (the soap film thickness field) which turns out to be highly sensitive to the presence of energy transfers. Keywords : Polymer physics, Interfacial Instabilities, Finite time singularities, Rheology, Extensional viscosity, Two dimensional turbulence, Soap films, Drag reduction, Passive scalar.
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https://tel.archives-ouvertes.fr/tel-00003794
Contributor : Yacine Amarouchene <>
Submitted on : Thursday, November 20, 2003 - 5:56:51 PM
Last modification on : Friday, May 10, 2019 - 12:24:07 PM
Long-term archiving on: : Friday, April 2, 2010 - 7:10:46 PM

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  • HAL Id : tel-00003794, version 1

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Yacine Amarouchene. Etude de l'Interaction Polymère-Ecoulement. Dynamique des Fluides [physics.flu-dyn]. Université Sciences et Technologies - Bordeaux I, 2002. Français. ⟨tel-00003794⟩

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