脉冲吹气对无缝襟翼翼型气动性能的影响

只有采用足够小的能量输入，获取更大的空气动力收益后，主动流动控制才有可能在真实飞机上获得更广泛的应用。脉冲吹气比定常吹气所需能量更少，控制效果更好，在改善翼型气动性能上得到广泛的研究。数值模拟了脉冲频率、占空比、动量系数等参数对无缝襟翼翼型升阻特性的影响规律，研究表明，脉冲频率接近于涡脱落频率时增升效果最好，当脉冲频率小于涡脱落频率时，阻力增加，当脉冲频率为涡脱落频率2倍时，阻力减小最多；动量系数较小时，占空比越小，冲击效应越强，增升效果越好；动量系数小于临界动量系数时，脉冲吹气增升效果优于定常吹气，当动量系数大于临界动量系数时，脉冲吹气控制效果低于定常吹气。研究脉冲吹气参数对翼型性能的影响规律，对采用周期性激励增升减阻、舵面增效的飞行器设计具有一定参考意义。

Influence of pulse blowing on slotless flap airfoil aerodynamic characteristics

Only when small enough energy input can obtain greater aerodynamic performance gains, and the flow control technology can be widely used in the real aircraft. Compared with steady blowing, pulse blowing needs less energy and results in more efficient control effect, so it is more used in lift enhancement. The effect of pulse frequency, duty cycle and moment coefficient on the aerodynamic characteristics of a slotless flap airfoil is studied by numerical simulation. The results show that the optimal pulse frequency for lift increment approximately equals the vortex shedding frequency, the drag increases when the pulse frequency is lower than the vortex shedding frequency, and the optimal pulse frequency for drag reduction is about twice the optimal lift increment frequency. When the moment coefficient is small, lift increases with the decrease of the duty cycle. When the moment coefficient is lower than the critical moment coefficient, pulse blowing is more sufficient to improve lift performance, but when the moment coefficient is higher than the critical moment coefficient, steady blowing is the best choice. The investigation can provide some reference for using periodic excitation to increase lift, reduce drag and enhance maneuvering surface efficiency in the design of aircraft.