Last Monday we performed turbulence measurements in our new 22kW open-jet wind-tunnel at the Simtec facility (see also New Wind-Tunnel.
The turbulence level is a very important parameter in wind-tunnel technique since it indicates the degree to which experiments in different tunnels can be compared as well as how measurements performed on a model can be applied to the real world.
A single channel hot-wire probe from Dantec Dynamics has been used. Measurements have been performed at various airspeed and various locations from the exit area. The results are very promising. The careful design of the wind-tunnel with screens and honeycombs seems to be paying off. Following a diagram comparing the turbulence levels of various wind tunnels: