Effects of Grit Roughness and Pitch Oscillations on the S812 Airfoil

An NREL S812 airfoil model was tested in the Ohio State University Aeronautical and Astronautical Research Laboratory 3 x 5 subsonic wind tunnel under steady state and unsteady conditions. The test defined baseline conditions for steady state angles of attack from -20 degrees to +40 degrees and examined unsteady behavior by oscillating the model about its quarter chord pitch axis for three meanangles, three frequencies, and two amplitudes. For all oscillating cases, Reynolds numbers of 0.75, 1, 1.25, and 1.5 million were used. In addition, the above conditions were repeated after the application of leading edge grit roughness to determine contamination effects on the airfoil performance.