Paper Number
SC23 

Session
Suspensions, Colloids, and Granular Materials

Title
Connections between bulk rheology and microstructure of dense granular flows at the flow-arrest transition

Presentation Date and Time
October 22, 2019 (Tuesday) 2:45

Track / Room
Track 2 / Room 304

Authors (Click on name to view author profile)

  1. Srivastava, Ishan (Sandia National Laboratories)
  2. Silbert, Leonardo E. (Central New Mexico Community College, School of Math, Science, and Engineering)
  3. Grest, Gary S. (Sandia National Laboratories)
  4. Lechman, Jeremy B. (Sandia National Laboratories)

Author and Affiliation Lines (in printed abstract book)
Ishan Srivastava1, Leonardo E. Silbert2, Gary S. Grest1, and Jeremy B. Lechman1
1Sandia National Laboratories, Albuquerque, NM 87185; 2School of Math, Science, and Engineering, Central New Mexico Community College, Albuquerque, NM 87106

Speaker / Presenter 
Srivastava, Ishan

Text of Abstract
Granular materials exhibit a dynamical transition between arrested and steady flowing states at a critical stress ratio. Although their simple-shear steady-state rheology is now well characterized, the transition itself is accompanied by interesting dynamical phenomena such as transient dilatancy, shear jamming and a non-trivial evolution of the granular fabric, most of which are not well understood. The transition is highly stochastic which makes its continuum modeling quite challenging. Additional complications are introduced by a dependence on loading paths, with important differences between transient rheology of shear-induced and compression/extension-induced flows. We demonstrate complex rheological scenarios that emerge at the flow-arrest transition of granular materials using discrete element simulations. The stochastic nature such transitions is highlighted. Using a standard rheological basis applicable to viscometric and extensional flows, connections between the evolution of granular fabric and bulk rheology are illuminated in various flow scenarios, thus providing significant microstructural inputs towards the development of rheological laws beyond steady state and simple shear granular flows.