Paper Number
SC42 

Session
Suspensions, Colloids, and Granular Materials

Title
An experimental study on the shear-induced migration of particles in yield stress fluids

Presentation Date and Time
October 23, 2019 (Wednesday) 5:25

Track / Room
Track 2 / Room 304

Authors (Click on name to view author profile)

  1. Rashedi, Ahmadreza (Ohio University & Universite de Bordeaux, Mechanical engineering)
  2. Lenoir, Nicolas (Engineering Institute Univ. Grenoble Alps, Laboratory 3SR - UMR 5521)
  3. Ovarlez, Guillaume (Universite de Bordeaux, Physical Chemistry)
  4. Hormozi, Sarah (Ohio University)

Author and Affiliation Lines (in printed abstract book)
Ahmadreza Rashedi1, Nicolas Lenoir2, Guillaume Ovarlez3, and Sarah Hormozi4
1Mechanical engineering, Ohio University & Universite de Bordeaux, Athens, OH 45701; 2Laboratory 3SR - UMR 5521, Engineering Institute Univ. Grenoble Alps, Grenoble Cedex nine, Grenoble 38041, France; 3Physical Chemistry, Universite de Bordeaux, Pessac, Bordeaux 33600, France; 4Ohio University, Athens, OH 45701

Speaker / Presenter 
Rashedi, Ahmadreza

Text of Abstract
Dense suspensions of solid particles in complex fluids are ubiquitous in many natural and industrial settings. In a nonhomogeneous shear flow, it has been shown that the particles migrate from regions of high shear rates to regions of low shear rates, so-called Shear-Induced Migration (SIM) of particles, which is well studied for Newtonian suspending fluids. However, our knowledge of SIM of particles in complex fluids is limited. The main challenge is that even in the creeping flows, the kinetics of migration not only depends on the shear strain but also depends on the shear rate. Therefore, in order to study SIM in complex fluids, we need to have access to instantaneous distribution of particles in the flow. We have developed a new experimental technique based on X-ray radiography [1] with high spatial and temporal resolutions to study the SIM of particles in complex fluids. We used this technique to study SIM of particles in a yield stress fluid in a wide-gap Taylor Couette geometry. We present our experimental results and refine the recent model framework for the dispersion of solids in yield stress fluids [2]. References:[1] Gholami, M., Rashedi, A., Lenoir, N., Hautemayou, D., Ovarlez, G. and Hormozi, S., 2018. Time-resolved 2D concentration maps in flowing suspensions using X-ray. Journal of Rheology, 62(4), pp.955-974. [2] Hormozi, S. and Frigaard, I.A., 2017. Dispersion of solids in fracturing flows of yield stress fluids. Journal of Fluid Mechanics, 830, pp.93-137.