Active Flow Control with an Oscillating Dropped-Hinge Flap

高升力系统将飞行范围扩展到低空速，并实现了较短的起飞和降落距离。为了进一步提高经典高升程系统的性能，人们正在研究主动流动控制系统。本项目所研究的主动流动控制方法可以抑制水流的分离，这在RWTH和TUM联合项目中使用数值方法的初步工作中得到了证明。为了实现主动流量控制，高升程配置的下垂铰链襟翼绕铰链点作简谐振荡运动。摆动的下垂铰链襟翼对升力系数的影响强烈依赖于振荡频率。因此，在我们自己的前期工作中，主动流影响的影响只在一定的频率范围内表现出来。确定了振荡间隙尺寸对间隙流动的影响和振荡襟翼表面对近壁面边界层的影响。为了更好地了解这些影响，我们进行了数值和实验研究，一方面通过跟踪扰流板来改变振荡间隙的宽度，另一方面通过跟踪振荡频率和幅度来改变振荡间隙的宽度。参数研究将被用来确定在大范围的攻角和襟翼角度范围内使用振动的下垂铰链襟翼进行主动流动控制的潜力。此外，还将通过数值研究的方法考虑雷诺数的影响。

High-lift systems extend the flight envelope to low airspeeds and enable short take-off and landing distances. In order to further improve the performance of classical high-lift systems, active flow control systems are being investigated. The method for active flow control investigated in this project can suppress the separation of the flow, as was shown in preliminary work within a joint project between RWTH and TUM using numerical methods. To achieve active flow control, a dropped-hinge flap of an high-lift configuration is set into harmonic oscillating movement around the hinge point. The influence of an oscillating dropped-hinge flap on the lift coefficient strongly depends on the oscillation frequency. Thus, in our own preliminary work, the effect of the active flow influence was only shown in a certain frequency range. Effects of the oscillating gap size on the gap flow and of the oscillating flap surface on the boundary layer near the wall were identified as influencing variables. In order to better understand these effects, numerical and experimental studies are carried out to vary the oscillating gap width by tracking the spoiler on the one hand and the oscillation frequency and amplitude on the other. Parameter studies will be used to determine the potential for active flow control with an oscillating dropped-hinge flap over a wide range of angles of attack and flap angles. In addition, the influence of the Reynolds number will be considered by means of numerical studies.