Capillary Rise Profile
By Tom Kodger
2μm beads dispersed in clean 18.2MΩ water at a 1:1000 dilution (2wt% stock concentration). Beads were washed to remove any trace surfactant present in the bead stock. Capillaries with a 400μm ID and 1mm OD.
How does the flow field go from a uniform capillary rise at the interface to a Poiseuille parabolic flow at a distance away from the interface?
Use PIV (particle image velocimetry) to find flow field.
The high flow field in the middle (Poiseuille) is driven toward the wall at the interface. This concludes that the flow velocity at the center of the channel is greater than the capillary rise velocity, otherwise this condition would violate conservation of momentum.