Flow of lubricated granular material on an inclined plane

We have studied the gravity driven flow of spherical shaped, millimetric sized granular material coated with aspherical, micron-sized, near frictionless lubricant particles. Experiments were performed on an inclined plane using two different particles for varying concentrations lubricant. The particle volumetric rate exhibits a non-monotonic behavior increasing concentration. It shows increase at lower concentration followed by decrease higher adhere to surface thereby reducing inter-particle friction. However, presence damps out collision momentum transfer. Non-monotonicity in observed is then conjectured arise due competing effects friction and collision. present work overall therein provides simple experimental system characterize added pharmaceutical other relevant industrial applications.