FIG. 3.

Modest displacements due to $〈{\mathbf{F}}_{\text{DEP}}〉$ are amplified in the obstacle array geometry. This amplification increases with increasing device length, increasing the mean collision frequency (i.e., the collision frequency for all particles of a given diameter averaged over the length of the device) for particles with f_CM > 0 and decreasing the collision frequency for particles with f_CM < 0 (shown here for 2a = 22 μm and Δ = 4 μm).