Discrete characterization tools for cohesive granular material

Granular flow is important scientifically as well as industrially. Often, c ohesive forces between grains are the norm, rather than the exception; yet, the majority of research in granular materials has been directed at cohesi onless materials. Due to the relatively large body of knowledge regarding c ohesionless flows, gaining an understanding of the transition from cohesion less to cohesive behavior is of particular interest. In this work, we study systems where the predominant mode of cohesion is due to interstitial liqu id (capillary cohesion). Both computations and experiments are used to expl ore a range of cohesive strengths (from cohesionless to cohesive,). We prop ose two discrete characterization criteria, based on the physical picture o f liquid-induced particle-level cohesion, which seem to work well in both s tatic and flowing systems. Finally, we address limitations of this approach and discuss potential extensions to systems dominated by other modes of co hesion. (C) 2001 Elsevier Science B.V. All rights reserved.