Active control of flow over a three-element airfoil in unbounded flow and in ground effect

The focus of this paper is on Active Flow Control (AFC) applied to modify the flow field of a three-element airfoil in unbounded flow and in ground effect. MD 30P30N airfoil is used as the three-element airfoil. CFD simulations are performed using ANSYS Fluent. Reynolds-Averaged Navier-Stokes (RANS) equations are solved in conjunction with the Spalart-Allmaras (SA) turbulence model. First, the relationships between the flap deflection angle and the lift coefficient in unbounded flow and ground effect are determined. Then, AFC is employed by injecting a uniform jet (blowing) or a synthetic jet at the leading edge of the flap. After AFC is employed, the lift coefficient is enhanced significantly using both flow control methods compared to the lift coefficient without flow control in the unbounded flow as well as in ground effect. The flap deflection angle for stall increases to 50 degrees for both control strategies employing the uniform blowing or the synthetic jet. In unbounded flow, the lift coefficient is enhanced significantly by AFC with synthetic jet and the flap deflection angle for stall increases to 45 degree; however for AFC with the uniform blowing, the effect on lift enhancement is relatively smaller.