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Extended velocity range for wind tunnel measurements


The use of laser Doppler anemometers, extended under technical aspects, allowed the velocity range for the calibration of conventional anemometers in wind tunnels to be extended in the range of small velocities.

Within the frame of the realization and dissemination of the flow velocity of gases, the velocity range was extended with regard to the calibration of anemometers for small velocities down to 0.2 m/s. As the calibration of anemometers in wind tunnels requires defined flow velocities at the place where the anemometer is installed, and as the measurement uncertainties of anemometers based on differential pressure measurements increase towards small flow velocities of < 4 m/s due to increasing uncertainties for the pressure measurement, laser Doppler anemometers are now used for both the measurement of the flow velocity in the wind tunnel and for the control and stabilization of the flow velocity during the calibration process – among other things also to take blockage effects into account.

Contact person:

Harald Müller, FB 1.4, AG 1.41, E-mail: harald.mueller@ptb.de