扰动来流下声控机翼分离流动的研究

本文介绍在扰动来流下声控机翼流动的试验装置、低速大攻角时的声控效果以及附面层中流动参数的变化规律，并由此得出：随着来流湍流度的增加，因声激励而产生的附面层中大尺度有序结构涡（ＬＳＯＳＶ）的脉动速度幅值Ｖｌ、湍流度增量ｕ′ａ／Ｕ∞以及升力系数增益△ＣＬ均将迅速减小，而激励声压级有效阈值ＳＰＬｅｆｆ则随之逐渐增大。周期性脉动来流在沿机翼附面层流动中急剧衰减，并对机翼分离流动（包括有或无声控）基本上没有什么影响。

ACOUSTIC CONTROL OF SEPARATED FLOW OVER A 2-DIMENSIONAL AIRFOIL AT DISTURBED INCOMING FLOW

The effects of disturbed incoming flow on the acoustic control of separated flow over a 2-dimensional low speed airfoil under high incidence have been investigated experimentally,including the benefits of acoustic excitation,the influence of parameters of exciting sound,and the variation of flow parameters in the boundary layer.The testing results indicate that,the flow velocity fluctuation of Large Scale Organized Structure Vorticity (LSOSV) v l and the benefit of turbulence intensity in the boundary layer u ' a/U ∞,the benefit of lift coeffecient,induced by exciting sound,will rapidly decrease along with the increase of turbulence intensity in the incoming flow.But the effective threshold value of sound pressure level will still enlarge gradually.It is also shown that,because of the rapid attenuation of oscillating velocity amplitude △ U ∞/U ∞ along the flow direction at natural flow field without exciting sound,the oscillating incoming flow has no effect on the benefits of acoustic excitation for the low speed 2-dimensional airfoil by and large.