Levich Institute Seminar Announcement, 09/13/2016
Steinman Hall, Room #312
(Chemical Engineering Conference Room)
Dr. Farhang Radjai
Massachusetts Institute of Technology
Visiting Scientist from CNRS
"Granular Flows: Insights from Numerical Simulations"
The rheology of granular flows and dense suspensions is controlled by steric constraints, geometrical disorder and intimate interactions of particles. From extensive numerical simulations, I discuss subtle geometrical effects that underlie the shear strength and dilatancy of granular flows. In particular, I show that fully-developed flows are characterized by a generic structural anisotropy that reflects the range of accessible geometrical states constrained by steric exclusions. Then, I present a simple approach for stress partition that involves both structural and force anisotropies, and leads to a general expression of the shear stress. I show how the application of this model allows one to account for effects of particle shape, size distribution, cohesive interactions and a suspending fluid on the shear strength.
BRIEF ACADEMIC/EMPLOYMENT HISTORY
I graduated from the University of Paris-Orsay with a Master in theoretical physics. In 1995, I obtained my PhD degree on friction and collective effects in granular materials at the same University. After two years of postdoctoral research in Duisburg University, I joined the French National Center for Scientific Research (CNRS) as full-time researcher in University of Montpellier, South of France. In 2004, I was appointed as CNRS Director of Research and pursued my research work as head of the research team « Physics and Mechanics of Discrete Materials ». In 2014, I joined the MIT-CNRS laboratory « Multiscale Material Science for Energy and Environment » in MIT, where I work on bottom-up modeling of multiphase materials.
RECENT RESEARCH INTERESTS
Rheology of granular flows and denses suspensions, multiphase materials, soft-particle materials, root-soil interactions, homogenization of granular materials, cemented materials, particle breakage effects and milling of powders and grains.