  Wave phenomena in vibrofluidized dry and partially wet granular materials
confined in a quasi-two-dimensional geometry are investigated with numerical
simulations considering individual particles as hard spheres. Short ranged
cohesive interactions arising from the formation of liquid bridges between
adjacent particles are modeled by changing the velocity dependent coefficient
of restitution. Such a change effectively suppresses the formation of surface
waves, in agreement with previous experimental observations. The difference in
pattern creation arises from the suppressed momentum transfer due to wetting
and it can be quantitatively understood from an analysis of binary impacts.
