The calibration of anemometers made for measuring the speed of air is performed in wind tunnels, which allow us to ensure a stable and homogenous velocity field. Due to the presence of a measuring object, the so-called “blockage effect” appears in the test section, which causes disturbances in the velocity field. The size of the blockage effect generally depends on the type of anemometer used and the ratio between the anemometers cross-section and the effective surface of its test section. Blockage effect can significantly affect the results of the calibration, so having an extensive knowledge about the speed profile of the test section is crucial for any further correction of the results of the calibration or to lower any kind of measuring uncertainty regarding the blockage effect. By using a wind tunnel and Doppler’s laser anemometer (LDA) we had performed the calibration of the vane anemometer at multiple different speeds and experimentally assessed the size of the blockage effect and the impact it has on the measuring uncertainty of the preformed calibration, all of which was done on the basis of the international guidelines for anemometer calibration. To get a better understanding and perception of the velocity conditions in the wind tunnel, we presented the speed profiles at different parts of the test section and analysed the results of the different blockage effect correction methods.
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