Experimental Investigation of Airfoil Performance in the Wake of a Circular Cylinder

Airfoil performance of a NACA 0012 held at static angles of attack from to 20° in the wake of a circular cylinder is investigated experimentally. Time-averaged airloads were measured for varying cylinder–airfoil streamwise distances, (based on cylinder diameter ), along with time- and phase-averaged particle image velocimetry. Changes in the cylinder wake flow structure govern airfoil performance in the cylinder–airfoil interaction. For , the cylinder wake arrangement is a pair of counterrotating vortices in a side-by-side configuration that induce negative drag on the airfoil. As the cylinder–airfoil distance increases to , the cylinder wake arrangement becomes a von Kármán vortex street that induces an oscillating flow field. A leading edge vortex forms over the NACA 0012 as a consequence of the cylinder wake and delays airfoil stall. This work gives fundamental insight into how large turbulent scales affect airfoil performance in the context of ship–aircraft aerodynamics.