Hysteretic transition between avalanches and continuous flow in rotated granular systems

Experiments in drums or cylinders partly filled with a granular system and rotated constantly about their horizontally aligned axis of symmetry show a hysteretic transition from discrete avalanches to continuous flow if the r otation rate is adiabatically changed. Herein, we show that this hysteresis can be explained by the impact of global Langevin-type fluctuations in a r ecently proposed minimal model for surface flow along granular piles. For t oo large magnitudes of the fluctuations corresponding to almost elastic gra ins, the hysteresis vanishes. This might explain why molecular dynamical si mulations were not yet able to detect the hysteretic transition. (C) 1999 A merican Institute of Physics. [S1054-1500(99)01203-3].