Particle ordering in inertially focused microfluidic flows

We study inertially driven focusing of particles [1], which has recently been exploited in a controlled fashion in microfluidic devices [2]. In particular, we characterize the focusing as a function of particle and channel Reynolds number by reporting particle position in directions perpendicular to the flow, and a large distance from the fluid inlet. Focusing of dilute suspensions leads to a linear arrangement of particles whose spacing is primarily a function of concentration and channel aspect ratio. All results are compared with simulations, which provide mechanistic insights into particle behavior.\\ \\ $[1]$ G. Segr\'{e} and A. Silberberg, Nature \textbf{189}, 209 (1961). \\ $[2]$ D. Di Carlo, D. Irimia, R. G. Tompkins, and M. Toner, Proc. Nat. Acad. Sci. U.S.A. \textbf{104}, 18892 (2007).