Wind channels consist of one or more fans which create an air flow, rectifier elements which provide a uniform, non-blasted flow, a nozzle to accelerate the rate of air flow as well as the actual measuring range in which the investigations are carried out. The flow in the measuring distance should therefore be as uniform, parallel, low-turbulence and low-noise as possible.
The turbulence level in the wind channel makes a quantitative statement about the turbulent fluctuation rates. The measuring range can, as shown in the figure, be open, i.e., the flow is blown from the nozzle into a measuring hall and, at the other measuring hall side, it is caught by a receiver or collector, whereby a shear layer builds up between the moving air and stationary air in the measuring hall.
However, there are also closed measuring ranges in which the flow is also led through walls in the measuring range and slotted measuring ranges in which some of these walls have slots.