This fluid dynamics video, presented at the 66th Annual Meeting of the American Physical Society Division of Fluid Dynamics (Pittsburgh, PA), shows how dielectric colloidal polystyrene (PS) particles with a negative surface charge in a dilute suspension flowing through a microchannel can be manipulated and assembled into streamwise structures by using a combination of shear and an applied negative electric field along the streamwise direction. Interestingly, these structures are only observed within about 1 um of the wall, which also has a negative surface charge, and are not present in the bulk flow.
Categories: physics.flu-dyn