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Le séminaire hebdomadaire du laboratoire PMMH a lieu tous les vendredis à 11h, au premier étage Barre Cassan, campus Jussieu (plan).
Alice Pelosse
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France
Tel : (33) 1 40 79 45 22
Séminaire PMMH - Elisabeth Lemaire (INPHYNI, Nice)
Origins of shear-thinning in non-Brownian suspensions
The rheology of concentrated non-Brownian suspensions has undergone a small revolution in the last 15 years when the importance of the role played by solid contacts between particles was realized. Considering these contacts has allowed to explain the continuous or discontinuous shear-thickening in dense suspensions [1] and, more recently, the shear-thinning observed beyond the shear-thickening transition [2], i.e. in frictional non-Brownian suspensions [3].
I will start by presenting a number of questions about suspension dynamics that would remain unanswered if we didn't take particle-to-particle contact into account. I will then focus on shear thinning to show that the decrease in viscosity recorded as shear stress increases can be explained either by the variable friction between particles [4] or by the presence of adhesive forces between particles. To this aim, I will first show how the study of the microstructure of suspensions under shear has revealed the existence of solid contacts between particles and that they are made possible by the presence of roughness on the particle surface. I will then present some numerical results that show how solid friction between particles increases the viscosity of suspensions, and how modeling inter-particle contact by an elasto-plastic mono-contact gives a very good account of the shear-thinning observed in concentrated non-Brownian and non-adhesive suspensions. I will show this scenario is validated by the measurement of the friction coefficient between two particles using an AFM [4]. I will end by discussing the other possible origin of shear-thinning, namely the presence of adhesive forces between particles and I will show that the measurement of adhesive forces by AFM can be used to predict the shear thinning behavior of adhesive non-Brownian suspensions.
[1] R. Mari, R. Seto, J.F. Morris and M.M. Denn, J. Rheol., 2014, 58(6), 1693-1724.
[2] G. Chatté, J. Comtet, A. Niguès, L. Bocquet, A. Siria, G. Ducouret, F. Lequeux, N. Lenoir, G. Ovarlez and A. Colin, Soft Matter, 2018, 14(6), 879-893.
[3] L. Lobry, E. Lemaire, F. Blanc, S. Gallier and F. Peters, J. Fluid Mech., 2019, 860, 682-710.
[4] M. Arshad, A. Maali, C. Claudet, L. Lobry, F. Peters and E. Lemaire, Soft Matter, 2021, 17(25), 6088-6097.
Séminaires (5)
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Séminaire PMMH – Philippe Beltrame (U. Avignon)
Vendredi 27 mars de 11h00 à 12h00 - Salle réunion PMMH 1
Ratchet Effect for Selective Transport of Microparticles in Fluid Suspension
The ratchet effect enables directed transport of particles in noisy systems, even in the absence of a net force (zero bias). When exploited in periodic structures, this phenomenon paves the way for innovative applications in selective microparticle sorting. This seminar will present a theoretical analysis of (…) -
Séminaire PMMH – Jonas Miguet (MSC, Univ. Paris Cité)
Vendredi 3 avril de 11h00 à 12h00 - Salle réunion PMMH 1
Antibubbles : optical interferometry, gas transfers and acoustic signature
An antibubble is a spherical thin film of gas, that encapsulates a droplet, within a liquid medium. The typical size of an antibubble is one centimeter while the thickness of the gas film is of micrometric order. Because of the higher hydrostatic pressure at the bottom, the gas film undergoes a (…) -
Séminaire PMMH – Gautier Verhille (IRPHÉ)
Vendredi 10 avril de 11h00 à 12h00 - Salle réunion PMMH 1
Formation and fragmentation of fiber aggregate in turbulent flows
Fiber aggregates are commonly encountered in environmental and industrial flows (paper industry, fiber recycling, etc.). However, the physical mechanisms leading to their formation are still misunderstood. Hence, there is still no clear answer to simple questions such as : how long will it take for an aggregate to (…) -
Séminaire PMMH – Nicolas Roméo (James Franck Institute, Chicago)
Vendredi 17 avril de 11h00 à 12h00 - Salle réunion PMMH 1
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Séminaire PMMH – Pas de séminaire
Vendredi 24 avril de 11h00 à 12h00 - Salle réunion PMMH 1
Instructions générales pour les conférenciers
Le public du séminaire est très hétérogène (rien qu’au PMMH nous travaillons sur des thématiques très diverses, mécanique des fluides, des milieux granulaires, des solides, physique statistique, physique du mouillage, micro-fluidique, biophysique,...) l’objectif est donc de ne pas faire un séminaire trop spécialiste : au moins la première moitié du séminaire à un niveau accessible pour celui qui ne connaît rien sur le sujet.
Le séminaire a lieu à 11h. rendez-vous 15 minutes avant pour installer et tester la projection.
Le séminaire dure environ 45 minutes pour laisser un peu de temps pour discuter à la fin.
- Séminaires ESPCI-ENS de biophysique
- Séminaires du Département de Physique de l’ENS
- Séminaires du Laboratoire d’Hydrodynamique de l’X
- Séminaire de Mécanique d’Orsay (page web FAST)
- Séminaire de Mécanique d’Orsay (page web LIMSI)
- Séminaire de Mécanique des Fluides de l’Institut Jean le Rond d’Alembert
- Séminaires du laboratoire MSC, Paris VII
- Séminaires Gulliver
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