Fluctuation of a Bending Moment Acting on the Rotatng Blade of a Horizontal Axis Wind Turbine (Comparison of Experimental Results and Annular Momentum Theory) : Fluids Engineering

In this report, the bending moment in the root of a rotating blade was directly measured by strain gauges, and these experimental values were compared with the theoretical values estimated by annular momentum theory. In the experiment, a middle scale horizontal axis wind turbine having a diameter of φ6m was used. The maximum power of the turbine was 10 kVA. The number of blades was two. As a result, the following was found; (1) Both values (theoretical and experimental) agree well. (2) The mean values of flapwise moment in the blade root were about three times larger than those of chordwise moment. (3) The chordwise moment caused by the dead weight of the blade was very large compared with the chordwise moment caused by the fluid force. (4) The instantaneous moments in the blade root were about two times larger than those of the mean values per 1 minute.