Suspension Mixing and Segregation in 1D, 2D, and 3D Flows

Particles in concentrated flowing suspension in pressure-driven flows tend to migrate away from the walls toward the center of the channel. Demixing due to shear-induced migration inhibits mixing and near wall transport. We investigate the competition between mixing and segregation in flows with complicated geometries that generate 3D chaotic advection, resulting in nontrivial concentration patterns. Using high-speed confocal laser scanning microscopy, we directly image the microspheres to measure the interplay between chaotic advection and the 3D spatial concentration profile, local particle velocities, and suspension structure.