Purpose:Illustrate laminar flow by "unmixing" two fluids
Description:Glycerin forms a cylindrical shell between two plexiglass cylinders. The inner cylinder can be rotated, setting up a laminar flow in the glycerin. Using a long hypodermic syringe, blue dye is injected in a line in the glycerin midway between the two cylinders. As the inner cylinder is rotated several turns, the dye "mixes" with the glycerin. When the rotation is reversed, the dye "unmixes" and almost returns to its original state.
Below is a link to the schematic of the unmixing apparatus.