Observed and predicted particle dynamics driven by inertial flows within high aspect ratio microfluidic channels

Inertial focusing in microfluidic channels has been shown to be an effective and versatile method of passively arranging particles into specific streamlines and regulating interparticle spacing. As a result of the high precision and fidelity of particle ordering, there has been significant interest in using microfluidic devices for applications in cell encapsulation, particle–fluid separation, size-selective cell sorting, and flow cytometry. When predicting application-specific design parameters, such as channel dimensions and flow rates, it is necessary to rely upon relations connecting the inertial forces acting upon particles with geometric dimensions. In this study, we develop an empirical technique to measure transverse-flow particle velocities and provide a semiempirical model describing the lateral forces experienced by a particle subject to non-turbulent, finite Reynolds number flow in a rectangular channel.