Experimental study of the blockage effect of a vane anemometer in a small wind tunnel

This study investigates the blockage effect of a vane anemometer in a small, closed test section of an open circuit wind tunnel. The experimental analysis examines the axial and cross-sectional positions of the vane anemometer in the test section. The results show that the changes in the calibration results due to different vane anemometer positions are within 1 %. The observed relative differences are compared with the existing guidelines for estimation of the blockage effect. Furthermore, a comparison with a larger wind tunnel facility demonstrates good agreement between the results, suggesting minimal systematic errors due to the blockage effect. The study underscores the potential using the variation in calibration results around the primary calibration point as a possible method to estimate blockage effect contribution to uncertainty in small wind tunnels.