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Interactions hydrodynamiques lors du transport de particules en fluide newtonien et non newtonien

Abstract : This work deals with the study of the hydrodynamic interactions effects on the movement and the transport of spherical and cylindrical particles in non-Newtonian fluids. Some important results were obtained to explain the physics of suspensions in non-Newtonian fluid. We used the Ostwald model which describes well the effects of shear-thinning and shear-thickening which characterize most non-Newtonian fluids. The first result was to show how the fluidity index affects the behavior of suspensions by the means of the hydrodynamic screen length around each particle. This enabled us to give the accurate values of the drag undergone by each particle in infinite medium, and to show the appearance of the Whitehead paradox in the case of the sphere starting from n=2 and of the Stokes paradox in the case of the cylinder starting from n=1. When n is close to these critical values, the determination of the hydrodynamic forces becomes very sensitive to inertia. The second important result for the industry of the injection of composite materials, was to show, using an inverse method, that the hydrodynamic interactions could induce a more or less important delay compared to the Newtonian case in the transport velocity of particles. The third important result for the analysis of the processes of aggregation of spherical or cylindrical particles, was obtained in the case of a spherical or cylindrical particle in sedimentation towards a fixed plane. An asymptotic calculation in the non-Newtonian case in the lubrication limit, compared successfully with that obtained numerically by the dynamic mesh method, enabled us to obtain the laws of evolution of the force undergone by these particles making contact with a plane. These last results find an application in the use of the dynamic surface force apparatus within the framework of the nanorheology.
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Contributor : Antoine Despeyroux <>
Submitted on : Wednesday, January 11, 2012 - 6:27:36 AM
Last modification on : Friday, July 17, 2020 - 2:58:26 PM
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  • HAL Id : pastel-00658705, version 1

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Antoine Despeyroux. Interactions hydrodynamiques lors du transport de particules en fluide newtonien et non newtonien. Mécanique des fluides [physics.class-ph]. Arts et Métiers ParisTech, 2011. Français. ⟨NNT : 2011ENAM0029⟩. ⟨pastel-00658705⟩

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