PETERS , François

Ce mémoire rédigé en vue de l'obtention de l'habilitation à diriger les recherches retrace mon activité de recherche depuis la fin de mon doctorat. Dans la première partie sont rassemblés les problématiques d'électrorhéologie auxquelles je me suis intéressé. Je décris d'abord la rotation spontanée d'un objet isolant dans un liquide peu...

In a recent paper, we have shown experimental results of ultrasound wave velocity and attenuation coefficient measurement in macroscopic suspensions. The experimental method was shortly described. This spectroscopy method allows measurement over a broadband frequency spectrum in a strong absorbing and high dispersive medium. The originality of...

We report experiments on a magnetic cohesive granular material made of steel spheres in the millimeter range. A magnetic field magnetizes the spheres, so that an interaction force between grains appears. A rotating magnetic field is applied parallel to plane of the quasi-two-dimensional cell containing the spheres so that only the time averaged...

We have measured the phase velocity and attenuation of a coherent acoustical wave propagating in a macroscopic suspension. The frequency range corresponds to resonant scattering of particles (kd ∼ π, where k is the wave vector and d the diameter of particles), at high concentrations (5% to 30%). We have developed a spectral method to measure...

National audience

The pressure-driven flow of a suspension of spinning particles in a rectangular channel is studied using an acoustic method. The suspension is made of insulating particles (PMMA) dispersed in a slightly conducting oil ( Ugilec + Dielec) and is subjected to a DC electric field. In such a case, the particles are polarized in the direction...

This paper reports experiments on the shear transient response of concentrated non-Brownian suspensions. The shear viscosity of the suspensions is measured using a wide-gap Couette rheometer equipped with a Particle Image Velocimetry (PIV) device that allows measuring the velocity field. The suspensions made of PMMA particles (31µm in diameter)...

In this paper, we report experimental evidence of Lorenz chaos for the Quincke rotor dynamics. We study the angular motion of an insulating cylinder immersed in slightly conducting oil and submitted to a direct current electric field. The simple equations which describe the dynamics of the rotor are shown to be equivalent to the Lorenz...

A particle-scale simulation method for non-Brownian suspensions at low Reynolds numbers is presented, which is well suited to nonlinear flows. It is based on a Fictitious Domain Method supplemented by sub-grid corrections (Gallier et al., 2014 [16]). In the original method, the standard sub-grid corrections involve the underlying suspension...

National audience

Poster : Rhéologie locale des suspensions concentrées GFR 44 Strasbourg

International audience

The shear-induced microstructure in a semi-dilute non-colloidal suspension is studied. A high resolution Pair Distribution Function in the plane of shear is experimentally determined. It is shown to be anisotropic, with a depleted direction close to the velocity axis in the recession quadrant. The influence of roughness on the interaction...

National audience

National audience

The fall velocity of a dense large ball in a suspension of neutrally buoyant non-Brownian particles subjected to horizontal oscillatory shear is studied. As the strain amplitude is increased, the velocity increases up to a maximum value before decreasing to the value that it would have in a resting suspension. The higher the frequency is, the...

Poster Workshop on flocculated suspensions - Champs sur Marne, 28-29 June 2012

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The fall velocity of a dense large ball in a suspension of neutrally buoyant non-Brownian particles subjected to horizontal oscillatory shear is studied. As the strain amplitude is increased, the mean velocity increases up to a maximum value before decreasing to the value that it would have in a resting suspension. The higher the frequency is,...

This work intends to evaluate the role of many-body long-range hydrodynamics by simulations of sheared neutrally-buoyant non-Brownian, non-colloidal suspensions. Three-dimensional simulations of sheared suspensions are conducted with and without long-range hydrodynamics, for a volume fraction range between 0.1 to 0.62 (frictionless) and 0.1 to...

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