On cup anemometer performance at high altitude above ground

In this paper, an experimental wind tunnel test campaign to assess the possibility of using cup anemometers at high altitude (similar to 20 km) is performed. The experimental procedure consists of measuring the evolution of the rotational frequency for different wind dynamic pressures for different cups and the center of rotation radius. With particular interest on the point at which the rotation stops for decreasing values of the dynamic pressure is considered as the limit value for the anemometer operation. The results show that large cup radius anemometer rotors present more stable behavior (its stopping point at low wind speeds being less affected by the cups' center rotation radius). The authors conclude that cup anemometers can be used at high altitude above ground. Results show that an anemometer equipped with a 40 mm cup radius rotor could be considered operative up to an altitude of 25 km above ground.