In this work, we applied discrete element method (DEM) based simulations to investigate the granular organization phenomenon recently observed in an orbital shaker. The simulation results capture the complex motion and self-organizing patterns of particles. When a single particle descends along the wall of an orbiting cylinder, the centrifugal and frictional forces acting on the particle lead to an oscillating trajectory. In contrast, when multiple particles descend from the top, they form a monolayer of a reproducible trapezoidal robust shape on the inner wall, being supported by particles from below and sides, while rotating with the cylinder. The simulation results confirm the hypothesis of auto-tuning of friction and reveal that there are three distinct regions in the monolayer with varying states of particle motion. Also, it explains the observation that the varying intensity of particle interactions induces the auto-tuning of friction. Particles dissipate the rolling energy through particle interactions and transition their state gradually from rolling to sliding within the monolayer, which subsequently increases the friction forces acting on the particles and balances the overall centrifugal force with the frictional force. This work is the first successful attempt to understand the granular organization phenomenon in orbital shaking by DEM simulations, and it may be beneficial to the design and operation of industrial equipment involving such granular systems.
- Discrete Element Method (DEM)
- Granular flow mixing
- Mixing in Orbital shaker
- Non-linear dynamics