Paper Number
SC11
Session
Suspensions & Colloids
Title
Oscillatory and history-dependent dynamics of shear banding in a thixotropic yield-stress fluid
Presentation Date and Time
October 15, 2018 (Monday) 4:10
Track / Room
Track 1 / Galleria I
Authors
- Wei, Yufei (University of Michigan, Chemical Engineering)
- Solomon, Michael J. (University of Michigan, Chemical Engineering)
- Larson, Ronald G. (University of Michigan, Department of Chemical Engineering)
Author and Affiliation Lines
Yufei Wei, Michael J. Solomon, and Ronald G. Larson
Department of Chemical Engineering, University of Michigan, Ann Arbor, MI
Speaker / Presenter
Wei, Yufei
Text of Abstract
We use time-resolved particle image velocimetry with high spatial resolution to study the onset and evolution of shear bands in a fumed silica suspension, a thixotropic yield-stress fluid. This fluid exhibits rich spatiotemporal dynamics of local velocimetry, including shear bands that evolve slowly, quickly homogenize, and periodically oscillate, with no sign of these velocimetric dynamics in the bulk rheology. We construct a simple constitutive model to explain this phenomenology. This model contains two dynamical variables – one for thixotropy and the other one for kinematic hardening (KH). Different from previous thixotropic KH models, our model allows the KH effect to decay after flow stops, which is physically due to the rearrangement of internal structures. With this relaxation, the model successfully captures important features of experiments. It can be made more realistic by including additional dynamics that allows model parameters to undergo history- and time-dependent changes.