Dynamic Stall Control Investigations on a Full Size Chord Blade Section

In the present investigations dynamic stall is controlled by a nose-drooping device, where the 10%-sealed leading edge part of a new supercritical airfoil section drooped down dynamically during the pitching motion of the blade model to alleviate dynamic stall. Both CFD-calculations as well as experiments have been accomplished for these investigations within the scope of the project ADASYS (Adaptive Systems) between the partners: ECD, EADS and DLR. Three different DLR-Institutes were involved in the project: Institute of Aerodynamic and Flow Technology, Institute of Aeroelasticity, both located in Göttingen and Institute of Flight Systems located in Braunschweig, Germany. Main emphasis in the present discussions is placed on the experimental investigations which have been carried out in the DNW-TWG wind tunnel facility located at DLR-Göttingen. A full size 0,3m chord blade section with 1m span (between the tunnel side walls) has been installed inside the adaptive wall test section of this tunnel. The model made of composite material was suspended in the forced pitch-oscillation test rig of the DLR-Institute of Aeroelasticity. In addition to the pitching motion of the model about its quarter chord axis, the 10% leading edge part (0,5m span) of the model was oscillated separately from the blade motion in different drooping modes and with phase-variations between blade motion and flap motion. The leading edge deflection has been achieved with piezoelectric actuator devices developed by EADS. the flap/actuator arrangement has been designed as a separate module which could easily be removed from the remainder of the model. In the present paper experimental results and comparisons with numerical data are discussed for steady as well as unsteady flow cases