Aerodynamic Performance of Airfoils with Tangential Synthetic Jet Actuators Close to the Trailing Edge

Abstract

Aerodynamic properties of an airfoil can be modified by trapping concentrations of vorticity close to the trailing edge. Experimental work has shown that synthetic jet actuators can be used to manipulate and control this trapped vorticity. A time-resolved detailed model is used to simulate the action of tangential-blowing synthetic jet actuators mounted near the trailing edge of the airfoil at low angle of attack. This detailed model resolves the temporal and spatial scales involved in the synthetic jet dynamics. The detailed synthetic jet model along with the Computational Fluid Dynamics (CFD) computations in which they are embedded are validated against wind tunnel data acquired by Dr Ari Glezer’s group at Georgia Tech. Numerical results show the effects of the actuators on the vortical structure of the flow, as well as on the aerodynamic properties. The main effect of the actuation on the time averaged vorticity field is a bending of the separation shear layer from the actuator toward the airfoil surface, resulting in changes in the aerodynamic properties. Similar to the experimental observations, full actuation of the suction side actuator reduces the pitching moment and increases the lift force, while the pressure side actuator increases the pitching moment and reduces the lift force. The effectiveness of the actuator is measured by the change in the aerodynamic properties of the airfoil in particular the lift (�Cl) and moment (�Cm) coefficients. Computational results for the actuator effectiveness show very good agreement with the experimental values over the range of 2 ◦ to 10 ◦ . While the actuation modifies the global pressure distribution, the most pronounced effects are near the trailing edge in which a spike in the pressure coefficient ( Cp), consistent with experimental results, is observed.