Experimental evidence of coupled-mode flutter in a two-meter-long non-rotating wind turbine blade

We have conducted a series of experiments on 30:1 scale wind turbine blade and observed coupled-mode flutter. This observation validates the theoretical studies that predict larger blades are susceptible to To conduct these experiments, we built scaled-down model 61-meter NREL 5 MW blade. The was approximately 2 meters long such ratios between its first torsional natural frequency flapwise frequencies were similar those full-scale important, because predictions suggest flutter occurs when one modes mode coalesce. In our as speed increased, turbulence induced vibrations initially in form oscillations blade’s mode, then second with region multi-modal between. It decreased increasing increased slightly. Then at critical speed, merged into indicating has occurred this speed.