Comportement macroscopique des écoulements à interface dynamique

Abstract : Scattered microscopic interfaces system in a fluid in porous medium brings non-linearity in macroscopic flow model. Whether these interfaces are regular or singular, they bring fundamental changes in streamlines or no t, macroscopic model changes are radical or not. Two types of interfaces system have been studied. The first one deals with the interface between two phases. Homogenization by asymptotic development in periodic medium bas been used to derive macroscopic laws, in porous medium, from microscopic laws in capillary. It bas been shown that planned interface, regular, should be distinguished from meniscus interface, singular. ln first case, pressure gradient ofboth phases are present in macroscopic law, but not capillarity. ln second case, homogenization needs first to salve some problems like phases prolongation, flow periodicity, triple point, and leads to a capillarity vector in macroscopic law, but not two pressure gradients. The second type of system deals with the structure interface which separates 1\\10 regions of specific flow mode in a one phase flow. The study of the macroscopic behaviour ofthese structured flows aims to contribute to the comprehension of theoretical basements of Darcy-Forchheimer law. Due to CFD-ACE code, numerical simulations have been perfonned through a loophole, for which effects of viscous and inertial forces have been evaluated. Results of these simulations show that no-periodicity, namely anisotropy, is a possible cause for quadratic correction appearance, but the major point is the singularity of the structure interface movement as responsible for quadratic tenD : instability of this interface enables an accumulation offluid at low velocity in loophole border.
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Theses
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http://docnum.univ-lorraine.fr/prive/INPL_T_2005_LUCAS_Y.pdf
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Submitted on : Thursday, March 29, 2018 - 12:35:16 PM
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Yann Lucas. Comportement macroscopique des écoulements à interface dynamique. Alimentation et Nutrition. Institut National Polytechnique de Lorraine, 2005. Français. ⟨NNT : 2005INPL016N⟩. ⟨tel-01749992⟩

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