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Accueil du site > Seminars > Séminaires théorie > Theory Club Jeudi 15 Juin 2017 à 13:00 en salle 646A. Alexandre Nicolas: "How do dense colloidal suspensions flow? An approximate derivation of macroscopic constitutive equations starting from the microscale".

Theory Club Jeudi 15 Juin 2017 à 13:00 en salle 646A. Alexandre Nicolas: "How do dense colloidal suspensions flow? An approximate derivation of macroscopic constitutive equations starting from the microscale"

Unless otherwise stated, seminars and defences take place at 11:30 in room 454A of Condorcet building.


How do dense colloidal suspensions flow? An approximate derivation of macroscopic constitutive equations starting from the microscale

Alexandre Nicolas

Abstract: A glass forms when a liquid is cooled rapidly or when the volume fraction of colloids in a suspension reaches high values, while crystallisation is avoided. The resulting material is a disordered solid that starts to flow only if one applies large enough shear. The theoretical description of these transitions from first principles is extremely challenging, owing to the paramount collective effects at play. Nevertheless, the emergence of rigidity in a quiescent supercooled liquid was theoretically rationalised in the 1970s-1980s [1] via the so called mode-coupling theory. In the 2000s the theory was extended to situations of (homogeneous) flow [2] and succeeded in reproducing major features of the rheology of dense colloidal suspensions. I will introduce these theoretical developments at a glance and present how tractable constitutive equations can be (approximately) recovered starting from the microscopic theory. I will put some emphasis on heterogeneities in the flow by exposing the difficulty of handling them and their crucial importance when it comes to practical problems such as the study of flow instabilities [3]

[1] Bengtzelius, Ulf, W. Gotze, and A. Sjolander. "Dynamics of supercooled liquids and the glass transition." Journal of Physics C: solid state Physics 17.33 (1984): 5915.

[2] Fuchs, Matthias, and Michael E. Cates. "Theory of nonlinear rheology and yielding of dense colloidal suspensions." Physical review letters 89.24 (2002): 248304.

[3] Nicolas, Alexandre, and Matthias Fuchs. "Shear-thinning in dense colloidal suspensions and its effect on elastic instabilities: from the microscopic equations of motion to an approximation of the macroscopic rheology." Journal of Non-Newtonian Fluid Mechanics 228 (2016): 64-78.

Jeudi 15 Juin 2017 à 13:00 en salle 646A


Contact : Équipe séminaires / Seminar team - Published on / Publié le 22 June 2017


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