Paper Number
SC34
Session
Suspensions and Colloids
Title
Drop impact: Complex fluids under extreme stress
Presentation Date and Time
October 11, 2022 (Tuesday) 4:45
Track / Room
Track 1 / Sheraton 4
Authors
- Driscoll, Michelle M. (Northwestern University, Physics)
- Shah, Phalguni (Northwestern University, Physics)
- Arora, Srishti (Northwestern University, Physics)
Author and Affiliation Lines
Michelle M. Driscoll, Phalguni Shah and Srishti Arora
Physics, Northwestern University, Evanston, IL 60208
Speaker / Presenter
Driscoll, Michelle M.
Keywords
colloids; flow-induced instabilities; jammed systems; suspensions
Text of Abstract
Complex fluids exhibit a variety of exotic flow behaviours under high stresses, such as shear thickening and shear jamming. Rheology is a powerful tool to characterise these flow behaviours over the bulk of the fluid. However, this technique is limited in its ability to probe fluid behaviour in a spatially resolved way. Here, I will show how we can utilize ultrahigh-speed imaging and the free-surface geometry in drop impact as a new tool for studying the flow of dense colloidal suspensions. In addition to observing Newtonian-like spreading and bulk shear jamming, we observe the transition between these regimes in the form of localized patches of jammed suspension in the spreading drop. This system offers a unique lens with which to study shear-thickening fluids, allowing us to obtain flow information in a spatially-localized manner, so that we can observe coexisting solid and liquid phases. Furthermore, we capture shear jamming as it occurs via a solidification front traveling from the impact point, and show that the speed of this front is set by how far the impact conditions are beyond the shear thickening transition.