Study on the Effects of Active Flow Control on Aerodynamic Performance of Two Airfoils in Tandem Configuration

Aerodynamic investigation of tandem airfoil configuration has so many applications in different industries that has become a topic of scientific interest since many years ago. One can name a lot of applications in this field such as the aerodynamic interaction between a wing and a tail or a wing and a flap of an aircraft, blades of a rotor and a stator in a compressor or turbine, the tandem blades in the rotor of a compressor, wings of an MAV, to name but a few. The primary objective of this research is to investigate the effect of active flow control (AFC) on two airfoils in tandem configuration, in which the upstream airfoil undergo pitching motion and the downstream airfoil is stationary. In the first place, the aerodynamic characteristics of airfoils in tandem configuration such as lift and drag coefficient is obtained when there is no flow control on the airfoils (clean case). Following this, the mentioned quantities are calculated for the airfoils when AFC has been applied on the forefoil. In order to analyze the effect of AFC and tandem configuration aerodynamic characteristics, the lift and drag coefficient of clean case is compared to those of the controlled case. The result suggests that AFC has caused the amount of C_L to grow significantly. It was also observed that the tandem configuration had little influence on the forefoil. On the other hand, the vortices coming from the upstream airfoil generated thrust on the hindfoil. In case of AFC, our results suggest that fluctuations of both lift and drag forces decrease in the hindfoil. It is worth mentioning that this research is among the firsts studying the effect of AFC on tandem airfoils and will pave the way for those who are interested in this field.