Flow Visualisation
Why Flow Visualisation?
Wind tunnel testing does not always rely on quantitative results. Sometimes it is actually more useful to see what the flow is doing rather than rely on force or pressure measurements. For this reason, various methods of flow visualisation have been developed and range from cheap to very expensive.
Short lengths of cotton or wool can be applied to a model to determine flow direction and regions of vorticity/separated flow
A mixture of clay and kerosene or oil and a flourescent dye is applied to the surface of the wind tunnel model. The tunnel is then run until a steady state condition is reached and a flow pattern is observed
A rake with smoke jets is installed in a tunnel to provide streams of smoke. The interaction of these smoke streams with the model are then visualised.
The wind tunnel is filled with smoke using a smoke generator. A laser sheet is then oriented alond the plane of interest to visualise the flow.
The wind tunnel is seeded with a vaporised oil based mixture such that the flow can be tracked using high speed cameras. This flow visualisation technique is unique as you also extract quantitative data.