Separation Control on a High-Lift Airfoil using Vortex Generator Jets at High Reynolds numbers

Kurzfassung

This work focuses on an active flow control system for a 2D two element high-lift airfoil at high Reynolds numbers up to Re= 9.2 · 106 and a Mach number of Ma= 0.15. Additional test cases at different Reynolds-and Mach numbers up to Re=12.21 · 106 at Ma=0.2 complete these measurements. The experiments were done in the cryogenic test facility DNW-KKK. The model is equipped with vortex generator jets close to the leading edge on the pressure side to suppress a turbulent leading edge stall. The experiments clearly show that the system can prevent stall but the gain of lift is reduced at high Reynolds numbers. The additional lift primarily depends on the flow rate. The influence of the actuation frequency is not clear but higher frequencies seem to be more efficient. In most cases dynamic blowing exceeds static blowing. A variation of the Mach number with constant Reynolds number and AFC parameters results in a constant increase of lift whereas the additional angle of attack becomes higher.