Hot-wire measurements of near wakes behind an oscillating airfoil

An experimental investigation was carried out to study the unsteady, near wakes behind an oscillating airfoil. the airfoil was given the harmonic pitching motion about the one-quarter chord axis at two reduced frequencies, 0.1 and 0.2. The amplitude of oscillation was 7.4 degrees. To assess the effect of mean incidence, the mean incidence of oscillation was varied from 104 degrees. When the mean incidence was 4 degrees, the airfoil was found to undergo a deep stall.