Unsteady Surface Pressures and Airload of a Pitching Airfoil

This paper presents unsteady surface pressure variations of a symmetrical NACA0012 section commonly used on Vertical-axis wind turbine blades. The section was tested at a Reynolds number of 90,000, mean incidence angles of 15 and -15, and a reduced frequency of 0.20. The experimental results show that the airfoil motion had significant effects on surface pressure distribution over the airfoil, leading to a formation and shedding of an energetic leading edge vortex which strongly affects the overall airload over the incidence range.