Numerical Investigation on the Coanda Effect Over the S809 Airfoil With Synthetic Jet Actuator at High Angle of Attack

Synthetic jet actuators (SJA) have shown their efficiency in manipulating the aerodynamic forces on airfoils and blades. Generally, the injection angle is assumed to be an important factor for the injection-based flow control techniques, especially in moderate separation. However, it is important to know the level of effectiveness and the aerodynamic mechanism through which a SJA may affect an airfoil at a high angle of attack. The present research studies the effects of angle between the injected flow and the surface’s tangent line (Coanda effect) over the S809 airfoil equipped with a SJA, using detached eddy simulation (DES). The airfoil is assumed to be at an angle of attack of 25°. Three different cases with jet flow angles of 5°, 15° and 25° are simulated at a constant momentum coefficient of 4.5×10⁻³. The SJA frequency is 125 Hz for all cases and the simulations are conducted at the Reynolds number of one million. The effects of the jet angle on the streamline, pressure distribution and lifts and drag values are investigated.