EXPERIMENTAL STUDY OF DELAYING THE STALL OF THE NACA 0020 AIRFOIL USING A SYNTHETIC JET ACTUATOR ARRAY WITH DIFFERENT ORIFICE GEOMETRIES

An experimental study on the effect of active flow control using a synthetic jet mechanism on stall delay for the NACA 0020 airfoil is conducted. The experiments are carried out at an open-suction type wind tunnel at Reynolds number 5x104. In the presented experimental study, aerodynamic force measurements of the airfoil with having different orifice geometries (cylindrical, rectangular, sinusoidal, v-type, inclined rectangular) are examined by using a speaker type actuator in synthetic jet mechanism. It is observed that all different orifice geometries are effective in delaying the stall angle of NACA 0020 airfoil. However, it is observed that the inclined rectangular type of synthetic jet geometry is the most advantageous in delaying the stall of the airfoil. The effects of geometric parameters of the actuator on lift and drag coefficient of the NACA0020 airfoil are investigated. Experimental results show that among the all-orifice geometries the rectangular orifice geometry is the most effective in increasing lift coefficient of the airfoil. It is observed that there is a maximum decrease in drag at 10 degrees where the stall occurs. In addition, the decrease in drag is observed after 10 degrees in rectangular, v-type and inclined rectangular orifice geometries.