Comparative study of the performances of a bio-inspired flexible-bladed wind turbine and a rigid-bladed wind turbine in centimeter-scale

The objective of this study was to investigate the behavior and performance of a novel flexible-bladed wind turbine (FBWT). A bio-inspired flexible-bladed centimeter-scale wind turbine was proposed, fabricated, and tested in a closed-loop wind tunnel. The performance of the FBWT was compared with that of a rigid-bladed wind turbine (RBWT) on four main aspects: electrical power output, start-up, blade coning, and yawing. The results showed that the FBWT had a higher power output than the RBWT: the maximum power coefficient, C_P, for the FBWT was 0.0870 at a tip speed ratio, TSR, of 3.20 and a wind speed of 1.83 m/s, while that for the RBWT was 0.0576 at a TSR of 3.56 and a wind speed of 2.04 m/s. The total time of the yawing phases with a 180° yaw-error angle was 6.12 s for the FBWT, which was 35.85% shorter than that of the RBWT. The blade-coning video footage showed that the blades of the FBWT underwent a substantial deformation and exhibited a passive pitching mechanism. These features allowed the FBWT to rotate and yaw faster than the RBWT. These results demonstrate the advantage of using biomimicry-based design and flexible materials for the fabrication of centimeter-scale wind turbines.