Interactions hydrodynamiques entre une sphère et une paroi texturée : approche, collision et rebond

Abstract : We investigate experimentally the dynamics of a sphere near a textured wall in a viscous fluid. High frequency laser interferometry is used to measure small displacements of the sphere. The texture is comprised of arrays of micro-pillars, whose geometrical parameters are systematically varied in order to study their influence of the dynamics of approach, collision and rebound of the sphere. Under creeping flow conditions, the sphere velocity near the textured wall is increased compared to the case of a smooth wall, as a result of the modification of the lubrication force due to the texture. We describe this modification using several hydrodynamic models. An effective slip length over the pillar array is measured. At moderate Stokes number the sphere inertia is non-negligible and the sphere can either stick or bounce off the wall. The sticking dynamics exhibit several regimes which can be described by taking into account the modification of the lubrication force by the texture. The micro-pillars modify the critical Stokes number for the bouncing transition. The micro-rebounds are characterized. Finally, the contact dynamics between the sphere and the pillars are described by a Hertz law modified by the texture geometry.
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https://hal.sorbonne-universite.fr/tel-01276376
Contributor : Thibault Chastel <>
Submitted on : Friday, February 19, 2016 - 11:53:53 AM
Last modification on : Thursday, July 4, 2019 - 11:00:06 AM
Long-term archiving on : Friday, May 20, 2016 - 11:01:35 AM

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  • HAL Id : tel-01276376, version 1

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Thibault Chastel. Interactions hydrodynamiques entre une sphère et une paroi texturée : approche, collision et rebond. Mécanique des fluides [physics.class-ph]. UPMC, 2015. Français. ⟨tel-01276376⟩

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