Hele Shaw Apparatus

The Hele-Shaw apparatus produces a flow pattern which is similar to that of potential flow. The flow in the apparatus is actually a highly viscous flow between two parallel plates with a very small gap between them.

This equipment basically consists of two parallel plates made of thick, transparent (glass or plastic) plates clamped together along the edges with a narrow (about 3 mm) space in between them.

The assembly of these two transparent sheets kept parallel with an uniform narrow space between them is provided with two small tanks of rectangular cross-section at the top end. The tanks are connected to the rectangular slit formed by the transparent sheets by a set of small holes (about 1 mm diameter) arranged in a row.

The holes from the two tanks are arranged to occupy alternate locations for communication. The other end of the rectangular slit is made to terminate in a circular hole, by gradually narrowing it after a specified distance from the tanks at the top. One of the tanks is filled with water and the other with a dye (say potassium permanganate).