Extended flexible trailing-edge on the flow structures of an airfoil at high angle of attack
Extended flexible trailing-edge on the flow structures of an airfoil at high angle of attack
复制标题
DOI：
10.1007/s00348-019-2767-5
复制
发表时间：
2019-07
影响因子：
2.4
通讯作者：
Xi He;Qinfeng Guo;Jinjun Wang
中科院分区：
文献类型：
--
作者：
Xi He;Qinfeng Guo;Jinjun Wang
摘要利用二维时间分辨粒子图像测速技术研究了柔性后缘对翼型大迎角流动结构的影响。实验模型由刚性NACA 0020翼型和柔性延伸后缘板组成。雷诺数范围为1.42 × 104 ~ 3.57 × 104（基于模型长度）。首先分析了柔性尾缘板的运动特性。当与流体相互作用时，柔性板进行强烈的周期性振动。随着雷诺数的增加，平板的变形更加复杂，变形幅度也更大。在这项研究中还捕获了流场。结果表明，柔性板的振动引起了尾缘涡的产生和脱落。此外，平板振动扰动还可以向上游传播，影响分离剪切层中前缘涡的形成。在尾流区，前缘涡和后缘涡的交替脱落过程与平板的振动耦合。此外，本研究进一步以基于尾流宽度的Strouhal数来标度振动频率。所有试验雷诺数下的Strouhal数均在0.14-0.21之间，表明流固耦合导致流动形成钝体尾迹。
AbstractA two-dimensional time-resolved particle image velocimetry experiment was carried out to investigate the effect of flexible trailing-edge on the flow structures of an airfoil at high angle of attack. The experimental model was composed of a rigid NACA0020 airfoil and a flexible extended trailing-edge plate. The Reynolds number ranged from 1.42 × 104to 3.57 × 104(based on the model length). The kinematic characteristics of the flexible trailing-edge plate were first analyzed. While interacting with the fluid, the flexible plate performed a strongly periodic vibration. The plate presented more complicated deformation and larger amplitude with the increase of Reynolds number. The flow field was also captured in this study. It was found that the vibration of the flexible plate caused the generation and shedding of the trailing-edge vortex. Furthermore, the disturbance of plate vibration could propagate upstream and influence the formation of the leading-edge vortex in the separated shear layer. In the wake region, the alternative shedding processes of the leading- and trailing-edge vortices were coupled with the vibration of the plate. Besides, this study further scaled the vibration frequencies with a Strouhal number based on the wake width. The scaled Strouhal numbers were in the range of 0.14–0.21 for all Reynolds number cases tested, which indicated that the fluid–structure coupling led the flow to form a bluff-body wake.Graphic abstractThe vibration patterns of the flexible trailing-edge plate at various Reynolds numbers.