Remarkable sensitivity to small differences in the size, shape and density of the constituent grains has been observed. However, most of this work relates to noncohesive granular matter. We investigate the progress of segregation in the presence of interstitial fluid by imaging the pile that results after bidisperse color-coded particles are poured into a silo. We show the importance of the viscous force in addition to the capillary force on both the progress of segregation and the angle of repose theta by changing the viscosity of the fluid. A second transition to segregation depending on viscosity is observed when the particles are completely immersed in the fluid.
Figure shows the effect of adding a small volume fraction of fluid to bidisperse glass beads.