Abstract

The manipulation of particles using inertial lift forces has broad implications in the separation, concentration and sorting of particles. In this work, we show that in the presence of a secondary flow, equilibrium locations of particles subject to inertial lift can be spatially varying. Using a well-defined microfabricated straight microfluidic channel with perpendicular permeate channels, we perform experiments over a range of particle sizes and inlet and outlet flow rates to highlight different focusing regimes. We show that a permeate flow can control the equilibrium location of particles and can be used to interrogate the balance between inertial and permeate forces.