Single-camera 3D particle tracking and application to shear-induced migration

In the experimental investigation of suspension flows, it is important to be able to precisely track suspended particles over a wide field of view. We present a cost-effective method for single-camera 3D particle tracking using digital image correlation and demonstrate its application to studying shear-induced migration. A speckle pattern is imaged through transparent spherical particles suspended in a viscous fluid and the resulting pattern distortion is used to deduce the particles’ 3D positions. Using this method, we examine the irreversible migration of millimeter-scale particles at low Reynolds number in an oscillatory, rectangular channel flow.  We report measurements of the migration dynamics and track interparticle contacts which are generally understood to be the source of irreversibility.