Paper Number
SC36 

Session
Suspensions, Colloids, and Granular Materials

Title
A new dimensionless number governing dethickening in orthogonally perturbed shear thickened suspensions

Presentation Date and Time
October 23, 2019 (Wednesday) 2:20

Track / Room
Track 2 / Room 304

Authors (Click on name to view author profile)

1. Ramaswamy, Meera (Cornell University, Applied Engineering and Physics)
2. Cohen, Itai (Cornell University, Applied Engineering and Physics)
3. Shetty, Abhishek (Anton Paar, Rheology Division)

Author and Affiliation Lines (in printed abstract book)
Meera Ramaswamy¹, Itai Cohen¹, and Abhishek Shetty^2
1Applied Engineering and Physics, Cornell University, Ithaca, NY 14850; ²Rheology Division, Anton Paar, Ashland, VA 14850

Speaker / Presenter 
Ramaswamy, Meera

Text of Abstract
When concentrated colloidal suspensions are under stress, their viscosity can increase by over an order of magnitude. Previous work has shown that this shear thickened viscosity can be tuned by applying fast oscillatory perturbations orthogonal to the primary shear flows in the system. In this talk, I show that dethickening in the regime where the primary shear flow has fully thickened the suspension, is governed by a single dimensionless parameter – the ratio of the orthogonal shear rate amplitude to that of the primary shear rate. In contrast, a second parameter is required to describe the data in the primary shear flow regime where the suspension is thickening. We also find that larger orthogonal shear rate amplitudes are required to break up force chains at lower volume fractions. Understanding these parameters will enable better strategies to tune the properties of shear thickening suspensions for applications ranging from 3D printing to the processing of cement.