Paper Number
SC22 

Session
Suspensions, Colloids and Granular Systems

Title
Shear thickening in suspensions: The effects of contact model

Presentation Date and Time
October 11, 2017 (Wednesday) 9:50

Track / Room
Track 3 / Crystal C

Authors (Click on name to view author profile)

1. Wilson, Helen J. (University College London, Mathematics Department)
2. Townsend, Adam K. (University College London, Mathematics Department)

Author and Affiliation Lines (in printed abstract book)
Helen J. Wilson and Adam K. Townsend
Mathematics Department, University College London, London WC1E 6BT, United Kingdom

Speaker / Presenter 
Wilson, Helen J.

Text of Abstract
We all know the phenomenon of shear thickening in concentrated cornstarch suspensions; indeed most of us will have used it as a hands-on demonstration experiments in our public engagement activity. Recently there has been a lot of research trying to understand the underlying mechanism of shear thickening. Some researchers have successfully replicated the phenomenon using a combination of inter-particle contact and a friction force that applies above some critical load [e.g. Mari et al, JRheol 58:1693, 2014; Seto et al, PRL 111:218301, 2014]. But it is still not entirely clear which properties of the inter-particle contact force are critical for shear thickening, and indeed whether these models really capture the local physics of the particle interactions. Using Stokesian Dynamics, we experiment with a variety of contact models, including the very simple model we first used in 2000 [Wilson & Davis, JFM 421:339-367, 2000] and some more sophisticated modifications to it. We find, perhaps surprisingly, that pure hard-contact asperities are not capable of predicting Discontinuous Shear Thickening; the compressibility used elsewhere is a critical component of the thickening behaviour.