Wet granular matter under vertical agitation

Abstract

We have studied the effect of small amounts of liquid on the dynamic behaviour of a granular system consisting of spherical glass beads under vertical agitation. The critical acceleration Γcrit at which fluidization sets in is found to increase strongly when liquid is added. It furthermore depends upon sample parameters such as the bead size and the shaking frequency. A simple model is proposed which accounts quantitatively for our results and suggests that fluidization by vertical agitation is mainly a surface phenomenon.