The free steam wind tunnel allows for the calibration of pressure and temperature probes. Its air supply is provided by a radial compressor, with a variable speed DC-motor (50kW, 2900rpm). The Witoszynski nozzles have a diameter of either 120mm or 200mm and the ratio between nozzle diameter and settling chamber length is 1:70 and 1:42 respectively. The maximum air speed of the wind tunnel is 100m/s, corresponding with a Mach number of 0,3, where a screen ensures a constant turbulent intensity of around 1%. Moreover, yaw and pitch angles can be comfortably changed using a traversing system. The operating point of the wind tunnel is set and monitored through the revolutions of the motor, the total pressure and total temperature in the settling chamber.

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