Discontinuous Change of Viscosity in a Sheared Granular Gas with Velocity-Dependent Restitution
Abstract
We investigate the rheology of a sheared granular gas composed of hard spheres with a velocity-dependent restitution coefficient. Using kinetic theory, we derive the shear viscosity and show that it exhibits an S-shaped dependence on the shear rate when the restitution coefficient switches between two values depending on the collision velocity. As a result, a discontinuous change of viscosity emerges between low- and high-shear regimes, both characterized by Bagnold-type scaling. While the phenomenology resembles the Wyart-Cates scenario for dense suspensions, the present transition arises purely from kinetic effects without frictional contacts or jamming.
Fields of Study & Subjects
Granular flow and fluidized beds
Geotechnical and Geomechanical Engineering
Heat and Mass Transfer in Porous Media
Publication details
- Journal / source
- Journal of the Physical Society of Japan
- Publisher
- Physical Society of Japan
- Volume
- 95
- Issue
- 5
- Publication date
- 21 April 2026
- Language
- EN