Vibrofluidic pumping, mixing, and separating of granular fluids

We report experimental observations of the behavior of granular fluids when subjected to horizontal, non-antiperiodic vibrations. We present quantitative measurements of pumping velocity, mixing length scale, and separation efficacy as functions of the frictional Froude number, a dimensionless group characterizing the ratio of inertia to the frictional resistance force. We compare the results to computational predictions and asymptotic analyses valid at high Froude numbers, and we discuss the implications for controlling granular fluids in lab-on-a-chip applications.