Figure 1.

Inertial focusing behavior in select channel geometries, terminating in expansions, is visualized schematically and by long exposure fluorescent imaging. Focusing performance was observed in channel expansions following: a) a horizontal (h/w < 1) high aspect ratio channel, b) an asymmetrically curved microchannel and c) a vertical (h/w > 1) high aspect ratio channel. d) Collage of long exposure particle streak images overlaying (a)–(c) at positions corresponding to increasing expansion channel width, W_C1, W_C2 and W_C3. e) One dimensional intensity profile of long-exposure particle streak images for (a)–(c). f) Width of particle streak in the channel expansion at positions W_C1, W_C2 and W_C3. g) Percent of channel area occupied by particles for each geometry shown in (e). Particle solutions with a concentration of 2×10⁶ beads/mL were flowed through channels at a constant Re_p=1.5.