Flowing Soft Matter: Bridging the Gap between Statistical Physics and Fluid Mechanics

June 30, 2014 — July 4, 2014


  • David Saintillan (University of Illinois at Urbana-Champaign, Urbana, IL, USA)
  • Denis Bartolo (ENS Lyon, France)

Polymer solutions, colloidal suspensions, emulsions, gels, granular matter, biological materials such as the cytoskeleton, bacterial suspensions, and cellular tissues are all complex materials lying at the interface between fluids and soft solids. Their mechanical properties result from the subtle interplay between their microstructure at the mesoscales, and the forces driving the flows either at the macroscale (e.g. sheared, and advected fluids) or at the microscale (e.g. thermal fluctuations, or local self-propulsion). 
Much research efforts have been devoted to understand the flow properties of these soft materials, in fields as diverse as soft-condensed matter physics, biophysics, materials science, chemical and mechanical engineering. Two main complementary descriptions have emerged in these different communities: on the one hand, these complex fluids can be described as continua using the equations of fluid mechanics with phenomenological constitutive laws; on the other hand, they can also be described using non-equilibrium statistical physics. In this context the constitutive laws and the mesoscale fluctuations are accurately described, but only yield minimalistic mechanical models. Both approaches have their merits, and their combination has proven to yield outstanding advances in the understanding of the large-scale mechanical properties of some complex systems such as polymeric fluids. However, over the last 20 years, interactions between the fluid-mechanics, soft-condensed-matter and statistical-physics communities have been scarce.
The objectives of this Summer School are twofold: first, present the participants with an overview of the exciting field of flowing soft matter, with focus on a few topics of active research interest; second, reconcile the statistical-physics and fluid-mechanics descriptions of these systems, by bringing together lecturers from both communities to discuss similar problems from the perspective of their own discipline. The contents of the School will articulate around three main themes:
(1) Fluctuations at all scales in Viscoelastic Fluids,
(2) Mechanics and Structure of Active Fluids,
(3) Flows and Arrest in Dense Suspensions and Granular Materials.
These themes have been selected to reflect current interests in soft-matter research, while being distinct enough from one another to provide a broad and general introduction of the field to the participants. Our purpose is to provide the Summer School participants with two complementary lectures on each theme: two researchers of different backgrounds will give 5 lectures each on a subject related to their research interests. 
The targeted audience for this Summer School will be advanced PhD students as well as postdoctoral researchers in departments of Physics, Biophysics, Engineering, and Materials Science.
The participants are also invited to give a short oral presentation on their research.


See also