Application Researches Of Single-outlet Oscillating Jets In Fluid Flow Control

Oscillating jets control is a kind of active flow control technologies, one of its' significant advantages is to use a smaller flow rate to control a larger flow area. In this paper, a single-outlet fluidic oscillator was designed and made, to be used as an actuator for fluid flow control.Firstly, a core "short-outlet" oscillator was designed and made based on the working mechanisms of single-outlet oscillator, and used for cavity resonance suppression. A so called "long-outlet" oscillator was designed and made based on the core oscillator, then applied it to separation flow control and the control of wingtip vortexes. Secondly, experiments on the characteristics of the oscillators were conducted by means of flow visualization, a sound level meter, a hot-wire anemometer and PIV; the results show that the air jets can sweep in high frequency and fan out in large angle, the jets can be fan out on the whole plane of the outlet equally, and the outlet jets have enough kinetic energy to influence a larger flow field.Finally,(1) Oscillator and normal jets actuator were used in the separation flow control; results show that: before stalled, both kind of jets have no influence on the lift-drag and pressure characteristics; but after stalled, the oscillating jets blow can significantly increase the leading- edge suction force on the upper surface as well as the lift, and the drag decreased obviously, while the normal jets blow have no such effects.(2) Two kind of actuators were used for wingtip vortexes control; results show that: in the conditions of upward blowing and along the spanwise blowing, both kind of jets flow were able to reduce wingtip vortexes, but the oscillating jets were more effective; on the condition of upward blowing, neither of the flow jets have the effects to reduce wingtip vortexes.(3) Oscillator was used in an "open" cavity resonance suppression; the results show that: when the input flow rate is 1m3/h, the Oscillating pure tones magnitude were reduced significantly, but increased the input flow rate cannot significantly reduce its' magnitude future more.