THE EFFECTS OF ACTUATION FREQUENCY ON THE SEPARATION CONTROL OVER AN AIRFOIL USING A SYNTHETIC JET

The simulation of separation control using a synthetic jet (SJ) is con-ducted around an NACA (National Advisory Committee for Aeronau-tics) 0015 airfoil by large-eddy simulation (LES) with a compact dif-ference scheme. The synthetic jet is installed at the leading edge of the airfoil and the e¨ects of an actuation frequency F+ (normalized by chord length and velocity of freestream) are observed. The lift-drag coe©cient is recovered the most for F+ = 6. The relationship between momentum addition by turbulent mixing and large vortex structures is investigated using a phase-averaging procedure based on F+. The Reynolds shear stress is decomposed into periodic and turbulent components where the turbulent components are found to be dominant on the airfoil. The strong turbulent components appear near the large vortex structures that are observed in phase- and span-averaged §ow ¦elds.