Volume 5 Issue 1 ( March 2018 )

In this work, the objective was to investigate the influence of Active Flow Control on the improvement of a DU96-W-180 airfoil aerodynamic performance. A numerical simulation was done for incompressible unsteady low Reynolds Number flow at high angle of attack. The innovative approach was the use of an “Active Slat” where the periodic blowing effect was achieved by periodically opening and closing the slat passage. The major benefit of this concept is being flexible to a desired operating condition. A new OpenFOAM^® solver was developed from the existing pisoFoam solver to simulate the active slat flow control technique. To get the best aerodynamic performance, the active slat should operate at the domain dominant frequencies. A Fast Fourier Transform (FFT) was performed to achieve the optimum slat excitation frequency. These frequencies will help in controlling the inherent instabilities in the boundary layer and thus improving the aerodynamic performance. Finally, active flow control simulations were applied using different excitation. Using the optimum FFT excitation frequency ( f = 0.68 in the wake region) yields the best aerodynamic improvement of all tested frequencies. Improvements in lift coefficient were achieved up to 8%. Hence, the slatted airfoil is superior to the conventional clean configuration airfoil.

Keywords: Active Flow Control, Active Slat, CFD, FFT, OpenFOAM.