  Liquid has a significant effect on the flow of wet granular assemblies. We
explore the effects of liquid induced cohesion on the flow characteristics of
wet granular materials. We propose a cohesion-scaling approach that enables
invariant flow characteristics for different particles sizes in rotating drums.
The strength of capillary forces between the particles is significantly reduced
by making the glass beads hydrophobic via chemical silanization. Main results
of rotating drum experiments are that liquid-induced cohesion decreases both
the width of the flowing region and the velocity of the particles at the free
surface, but increases the width of the creeping region as well as the dynamic
angle of repose. Also, the local granular temperature in the flowing region
decreases with an increase of the capillary force. The scaling methodology in
the flow regimes considered (rolling and cascading regimes) yields invariant
bed flow characteristics for different particle sizes.
