NUMERICAL INVESTIGATION OF FLOW CONTROL OVER AN AIRFOIL USING SYNTHETIC JETS AND ITS OPTIMIZATION

The synthetic jet parameters for a NACA 0015 airfoil are optimized at various angles of attack to maximize the lift to drag ratio (L/D). Unsteady, turbulent flows are computed using a Navier-Stokes flow solver in a parallel computing environment. The Spalart-Allmaras turbulence model is employed in all computations. The Response Surface Methodology (RSM) is employed for the optimization of synthetic jet parameters; the jet velocity, the jet location, the jet angle and the jet frequency. The optimization study is performed for a constant value of jet power coefficient. The jet slot size is used as a dependent parameter in the optimization studies. The optimization study has shown that the jet velocity and the jet location are the dominant synthetic jet parameters. The optimum jet location is observed to be moving through the leading edge and the optimum synthetic jet angle is observed to be increasing as angle of attack increases for the separated flows. The flow separation on the suction side of the airfoil is observed to be delayed after the application of the synthetic jet. The L/D ratio is increased especially at the post stall angle of attacks. The effectiveness of the synthetic jet decreases for the attached flows.