Determination of average lift of a rapidly pitching airfoil

by Linn, Anthony Blane.

Dynamic stall characteristics of an NACA–0012 was investigated to assess the possibility of augmented lift during sinusoidal angle of attack motion. Tests were conducted over a range of Reynolds numbers from 2.0 x 5 5 x 10 to 5.0 10 and reduced frequencies from 0.02 to 0.3. The data were recorded and plotted in a series of lift coefficient vs. angle of attack diagrams. These diagrams exhibited a hysteresis curve for the dynamic stall cycle similar to the results of previous investigators but without a large peak at high angles of attack. The data were also plotted as lift coefficient vs. angular cycle position. The average lift coefficient was computed for each set of test conditions and plotted with average lift coefficient vs. reduced frequency for each value of Reynolds number. The summary data indicate an increase of average lift coefficient with increased reduced frequency, and increased Reynolds number, although the increase was not monotonic over either Reynolds Number or reduced frequency. i Exordium