Figure 4.

Differential velocity ${(v}_{\mathrm{i}}-v_{\mathrm{o}})$ versus incoming velocity for a mixture of 10 µm (blue) and 15.7 µm (red) polystyrene microspheres at V_DEP = 6 V_pp and f = 1 MHz. Data points are colored according to optically measured size (see Figure 5).