| Circulation control (CC) has been demonstrated to enhance the lift force generated by a lifting surface without altering the physical angle-of-attack. Ongoing research at the Center for Industrial Research Applications (CIRA) involves the application of circulation control to vertical axis wind turbines (CC-VAWT) for increased power output. A NACA 0018 airfoil is modified to incorporate a rounded trailing edge with a radius of 0.25" and tested in the West Virginia University closed-loop subsonic wind tunnel. Augmentation of the two-dimensional lift coefficient associated with this circulation control design is measured using surface pressure integration from zero angle-of-attack through the stall point and then characterized for various blowing rates. At the maximum blowing rate, a lift increase of 60% is obtained with respect to the unmodified NACA 0018 airfoil and up to an 80% increase is observed compared to the modified NACA 0018 with no blowing. |
