Mechanism of perturbation-combined active control technique for asymmetric vortex flow over slender body at high angle of attack

Based on the determinability of asymmetric vortices flow over slender body under changeless round grain at high angle of attack, the effect of microblowing set in special position on the behaviors of asymmetric flow is discussed in this paper, including blowing momentum and circumferential locations of the microblowing hole of 0.5 mm in diameter on nose tip. A new kind of active control technique, named perturbation-combined active control technique, which combines the micro-grain and micro- blowing perturbation, was proposed on the basis of the above. This control technique can not only change the sign of side force of slender body arbitrarily through changing the vortices positions between yaw-left and yaw-right configuration, but also can make the magnitude of side force variable gradually even at bistable state of asymmetric vortex. Finally, the interferential mechanism of the perturbation-combined active control technique has also been concluded from this paper. The tests have been conducted at low speed wind tunnel with subcritical Reynolds number of 1.05×10⁵ at angle of attack α=50° in Beihang University, Beijing, China.