Viscous Crank Tank

Also known as the Laminar Un(Mixer).

This demonstration requires some preparation work a day ahead of time. Once the stored glycerin (~8L) is poured into the tank it is best to let it sit for at least a few hours to get rid of bubbles.

The coloured glycerine needs to be prepared by adding some food colouring into a beaker of glycerine, boiling it, and then letting it cool. This is to remove water content from the coloured glycerine. You can skip this step if there is some left from previous classes (usually kept in a bottle as shown in the photo below).

The demonstration consists of injecting coloured glycerin into the filled tank using the supplied syringe & tubing attachment. Then, the inner drum is turned slowly using the crank at the top of the tank. A slow rotation is best to preserve laminar flow.