Bistability and hysteresis in dense shear granular flow

Abstract

We consider dense Couette flow of inelastically colliding hard disks. Depending on the inelasticity of particle collisions and average density of particles, various flow regimes are found, and possible selection mechanisms are discussed. These regimes are investigated using both hydrodynamic equations and event-driven molecular dynamics (MD) simulations. One of the most intriguing flow regimes is the “plug flow”, where a solid-like cluster coexists with a fluid layer. The entire phase diagram of parameters is explored, and bifurcation diagrams are presented. We theoretically predict bistability and hysteretic behavior and confirm this prediction in MD simulations.