Experimental investigation of shock manipulation by the use of trailing edge brushes on a supercritical airfoil at transonic speeds

在整个项目中，研究了使用后缘刷子对上游移动压力波的退化及其对超临界BAC3-11翼型跨音速绕流的影响。波对激波形成的影响特别令人感兴趣。此前的纹影照片表明，激波的形成与压力波的聚集有关。初步实验结果支持了后缘刷子可以延缓激波形成到较高马赫数的理论。在单个工作包中，将分析波浪本身的行为，定义最有效的刷子参数，以及波浪和刷子对翼型空气动力学的总体影响。因此，刷子的直径和长度、马赫数和攻角都会有系统地变化。因此，将建立刷子的经验设计规范。此外，还将在RTWH亚琛大学空气动力学研究所的三音速风洞中进行实验，以验证结果并确保跨音速激波管(STK)中没有风洞干扰的影响。结果将在基于振动翼型压力波方程的波动运动物理模型中实现。最后，有可能通过相似规则将后缘刷子的设计标准和波浪运动的物理模型转移到实际飞行条件中。

Throughout the project the degradation of upstream moving pressure waves by the use of trailing edge brushes and their effect on the transonic flow around the supercritical BAC 3-11 airfoil is investigated. The influence of the waves on the formation of the shock is of special interest. Previous schlieren pictures indicate that the bunching of pressure waves is involved in the formation of the shock. The results of preliminary experiments support the theory that the trailing edge brushes can delay the shock formation to higher Mach numbers.Within the single working packages the wave behavior itself will be analyzed, the most effective brush parameters will be defined as well as the overall influence of the waves and the brushes on the airfoil aerodynamics will be deduced. Therefore the diameter and length of the brush, the Mach number and the angle of attack will be systematically varied. Hence empirical design specifications for the brush will be established.Additional experiments will be done in the trisonic wind tunnel at the Institute of Aerodynamics at RTWH Aachen University to validate the results and to make sure there were no influences of wind tunnel interference in the Transonic Shock Tube (STK).The results will be implemented in a physical model of the wave movement based on equations for pressure waves over an oscillating airfoil. Finally there will be the possibility to transfer the design standards of the trailing edge brush and the physical model of the wave movement via similarity rules to real flight conditions.