Parametric and dynamic modeling for synthetic jet control of a post-stall airfoil

Using the Reynolds-averaged Navier-Stokes equations, the effects of a localized synthetic jet actuator on post-stall flows are numerically investigated. The control jet is placed on the the suction surface near the leading edge of a NACA0012 airfoil. Significant modifications to the flow field due to the low momentum synthetic jet were obtained. These modifications generally have favorable impacts on the aerodynamic performance of an airfoil, such as lift increase and drag reduction. The effect of governing parameters of synthetic jet control on the flow field are discussed, including forcing frequency, blowing magnitude, blowing direction and jet location. Relations among these factors are discussed. Lift variations due to synthetic jet flow control are approximately modeled by a second-order nonlinear dynamical system, with the synthetic jet represented by a harmonic forcing term. Effects of governing parameters of a synthetic jet are discussed from a dynamical point of view based on these results. Comparisons are made between the dynamical model and the CFD simulations. This dynamical systems approach offers a qualitative explanation of the behavior of post-stall flows and the dominant mechanisms of their control.