Experimental studies on unsteady aerodynamics effect on the blade root load of HAWT field rotor

This paper describes the experimental results of field wind turbine rotor. The experiments are carried out with 10 m diameter of HAWT. The pressure distributions on the rotating blade are measured by the pressure transducers. The blade root moment are measured simultaneously by the strain gauges. The mean wind speed are measured by a sonic anemometer, the local velocity of the test section is measured by 7 holes Pitot tubes. The relation between the aerodynamic forces from pressure distribution and the blade root moment from strain gauges are discussed. The aerodynamic force shows the fluctuation by the local wind speed and direction change. The measured moment from strain gauges show the similar fluctuation. That includes the short period vibration of the blade natural frequency.