SELF-ORGANIZATION IN THE RAPID FLOW OF GRANULAR MATERIAL - EVIDENCE FOR A MAJOR FLOW MECHANISM

Based on the assumption that high-speed high-concentration sediment ma ss flows are primarily granular flows, their dynamic properties were s tudied. Such highly sheared granular flows are characterized by interp article collisions. This so-called rapid granular flow regime has been analysed using two-dimensional computer simulations. It is shown that granular flows at the microstructural level are governed by determini stic chaos. The bulk behaviour is characterized by self-organization a nd an attractor controlling the energy dissipation of the flow. The ex istence of this rapid granular flow attractor easily explains the line ar relation between drop height and travel distance of debris flows. A compelling consequence of the attractor is that rapid granular flow i s the major flow regime in debris flows.