Evaluation and Parameter Variation of Leading Edge Vortex Generators for Dynamic Stall Control on an OA209 Rotor Blade Section

A new concept of passive dynamic-stall control was developed and tested on an OA209 rotorcraft airfoil during two wind-tunnel test campaigns in 2004 and 2005. Small vortex generators are mounted at the leading edge of the rotor blade. At low incidence they are located close to the stagnation point and do not impact the flow field. At high angles of attack the so-called Leading Edge Vortex Generators (LEVoGs) induce longitudinal vortices which impact the suction side flow. It is shown that the use of LEVoGs can significantly increase the overall time-averaged lift while an unwanted negative pitching-moment peak is reduced compared with the clean-wing case. Furthermore, overall drag is reduced at dynamic-stall conditions. This report summarizes the performed parameter variations and documents the test points.