Seminars

PMMH’s weekly seminar is held every Friday at 11 am (map)

Contact :
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
responsables-seminaires (arobase) pmmh.espci.fr

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)

Vendredi 31 janvier de 11h00 à 12h00 - Salle réunion PMMH 1

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.

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Seminars  (4)

  • Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
    Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
    REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
    The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…)
  • Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
    Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
    REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
    The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…)
  • Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
    Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
    Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
    Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…)
  • Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
    Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
    Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
    Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…)

Information for the speakers

The audience is composed of people with rather heterogeneous backgrounds including specialists in solids, fluids, granular flows, statistical physics... so the idea is to keep your talk understandable by people not necessarily working in your field... The seminar time slot runs from 11am to noon so the best is to make the talk last around 45 minutes to leave some time for discussion.

Link to cofee seminar (internal, every Thursday)


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Practical information

Laboratoire : 01 40 79 45 22
Directeur : Ramiro GODOY DIANA
Codirecteur : Laurent DUCHEMIN
Administratrice : Frédérique AUGER (01 40 79 45 22)
Gestionnaire : Claudette BAREZ (01 40 79 58 53)
Courriel : dir (arobase) pmmh.espci.fr