Design of a single feedback channel oscillating jet actuator

In order to design an oscillating jet actuator conducive to separation control, a single feedback channel form of the actuator is studied with focus on the influence of parameters of the second throat and the expansion section on the oscillation characteristics of the jet as well as on the separation control effect of a deflection flap. The selection of geometric parameters for the actuator is summarized, and the separation control effect of the present designed actuator is compared with that of other typical actuators. The results show that, for an optimal design, the feedback section should maximize the deflection angle of the jet in the expansion part of the mixing section, and the mixing section should make the jet attach its wall. The second throat should make the jet momentum transfer uniformly in the flow field. If the second throat is too small or too large, it can reduce the jet deflection angle and make the jet momentum transfer non-uniformly in the flow field. The expansion angle of the expansion section should be increased to just enough to not prevent the jet from deflecting, as the jet can attach the wall asymmetrically if the expansion section is too large. A large outlet height can increase the jet offset, but if the outlet is too high, it can prolong the stagnation of the jet on both sides of the expansion section. Comparison of the separation control effect of different actuators shows that the drag reduction rate of the deflection flap with the present designed actuator is 3.8 times that of other typical actuators.