S弯进气道合成双射流流场控制特性分析

针对飞翼布局无人飞行器中S弯进气道明显流动分离和出口总压畸变等问题,提出了基于合成双射流的主动流动控制方法,建立了合成双射流的S弯进气道数值仿真模型。结果表明,在S弯进气道分离点附近施加合成双射流控制,在整个射流周期内通过“吹”“吸”接力可以有效抑制边界层流动分离,有效提升总压恢复系数。对比研究了合成双射流不同射流角度、射流峰值速度和激励频率对S弯进气道流场控制特性的影响规律。结果表明合成双射流与主流的角度越小,流动分离控制效果越好,较大射流峰值速度会对主流形成“阻挡”致使控制效果下降,激励频率与流场特征频率越接近控制效果越明显。

Analysis of flow field characteristics of S-bend inlet with dual synthetic jets

S-bend inlet leads to obvious flow separation and apparent total pressure distortion in unmanned aerial vehicle. To solve this problems, an active flow control method based on dual synthetic jets was proposed accordingly. The numerical simulation model of S-bend inlet with dual synthetic jets was established. The results show that dual synthetic jets can effectively suppress the boundary layer flow separation near the separation point of S-bend inlet through "blowing" and "suctioning" in the whole jet cycle, and effectively improve the total pressure recovery coefficient. The effects of different jet angles, jet peak velocities and jet frequencies on the flow field control characteristics of S-bend inlet were studied. The results shows that the smaller the angle between the dual synthetic jet and the main stream is, the better the flow separation control effect will be. The larger jet peak velocity will form a "blocking" effect on the main stream, resulting in a decrease in control effect. The closer the jet frequency is to the characteristic frequency of the flow field, the more obvious the control effect will be.