Role of Speed-dependent Friction on Flows of Tightly Packed Granular Particles: A Numerical Experiment

Cheng-En Tsai^1,2*, H.-C. Fan-Chiang³, Jih-Chaing (JC) Tsai¹

¹Insititute of Physics, Academia Sinica, Taipei, Taiwan
²Department of Physics, National Central University, Taoyuan, Taiwan
³Department of Physics, National Tsing Hua University, Hsinchu, Taiwan

* Presenter:Cheng-En Tsai, email:danner04290429@gmail.com

We design a 3D numerical experiment of tightly packed granular particles under a steady shear, and do an amendment on classic History-dependent Hertzian model that makes the friction coefficient speed-dependent. We successfully create the intermittency that would otherwise be missed in conventional models with a constant friction. This idea is based on our prior measurement that indicates a velocity-weakening friction on fluid-immersed PDMS surfaces. To characterize to what degree the friction is reduced, we also propose a dimensionless number. We find that in a certain range of this number, the granular flow shows intermittency and sudden releases of energy under steady shear.

Keywords: packed granular particles, granular flow, intermittency, speed-dependent friction, steady shear