Competition Between Chaos and Self-Organization
The multibody hydrodynamic interactions within flowing concentrated suspensions result in migration of particles toward regions of low shear. In a straight channel, this results in higher concentration in the center and fewer particles near the walls. By changing the geometry of these channels, flow in the cross-channel direction enhances mixing through chaotic advection. The primary question concerns the interplay between shear-induced migration and advection in the transverse direction producing 2D and 3D (chaotic) advection. More pointedly, which dominates self-organization or dispersion? Above, three different flows, demonstrating different segregation patterns in A) straight channels, B) channels with recirculation but with out chaotic advection, and C) channels with chaotic advection. Dark regions show higher particle concentration. Control of the underlying flow can enhance particle mixing or separations for lab-on-a-chip applications and industrial-scale processes.