SILO HICCUPS - DYNAMIC EFFECTS OF DILATANCY IN GRANULAR FLOW

The granular flow through an open silo is investigated experimentally. A mechanism based both on the dilation of the granular medium and an interaction with the interstitial gas causes the flow to stop at regul ar intervals. The experiments are carried out at different surrounding pressures Po, and it is found that the intermittent flow becomes cont inuous at sufficiently low Po, showing that the intermittency is linke d to the interaction the gas. The scaling of the average flow rate wit h particle size further supports our view of the gas-grain interaction . (C) 1998 American Institute of Physics. [S1070-6631(98)00912-X].