Rolling and sliding dynamics in centrifugal spreading

Centrifugal forcing is a usual method to spread a granular material. The dynamics of a particle in this system appears to change spectacularly according to the shape of the particle. We present a dynamical transition between a rolling and sliding regime and a purely sliding regime as a function of the friction coefficient and the elongation of the particle. This rolling/sliding motion is indeed observed, in-situ, for real particles. This simple effect of shape gives a physical interpretation able to explain the difference in the spreading velocity between round grains and elongated grains. 1 Applied Physics Letters, 2007 vol. 90, n° 2, 021918 doi : 10.1063/1.2424647 ha l-0 04 53 75 3, v er si on 1 5 Fe b 20 10 Author manuscript, published in "Applied Physics Letters 90, 2 (2007) p. 021918 p. 021918-3" DOI : 10.1063/1.2424647