Enhanced Power Extraction via Hybrid Pitching Motion in an Oscillating Wing Energy Harvester with Leading Flap

This study applied a hybrid pitching motion for an oscillating wing with a leading flap aimed at enhancing energy extraction efficiency. In the first half of the cycle, the hybrid pitching motion begins with a non-sinusoidal pitching motion for 0.0 ≤ t/T ≤ 0.25, transitioning to a sinusoidal pitching motion for 0.25 < t/T ≤ 0.50. The latter half of the motion mirrors the first one but moves toward the reverse direction. Hybrid motions combine the benefits of non-sinusoidal and sinusoidal pitching motions, enhancing the optimization of pitch angle variation. The findings show that hybrid motions for the wing fitted with an attached leading flap outperform both the single plate and the wing with an attached flap using sinusoidal pitching motion. The simulation was conducted with flap lengths ranging from 30% to 45% of the chord length and examined maximum pitching angles of the wing and the attached leading flap between 80° to 95° and 25° to 60°, respectively. By setting the pitch angles of the wing and leading flap to 85° and 45°, respectively, with the wing comprising 65% of the total length and the leading flap 35%, the proposed hybrid pitching motion with the leading flap generates a maximum power output of 1.276 that surpasses that of a sinusoidal pitching motion of 0.963 on an oscillating flat plate by 32.50%. This combination of hybrid pitching motion and a wing flap configuration is effective in improving the performance.