Investigation of flow at leading and trailing edges of pitching-up airfoil
Investigation of flow at leading and trailing edges of pitching-up airfoil
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俯仰翼型前缘和后缘流动的研究
DOI：
10.2514/3.12560
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
A. Krothapalli
中科院分区：
文献类型：
--
作者：
C. Shih;L. Lourenço;A. Krothapalli
在拖曳水池中对NACA0012翼型进行了等速上仰运动的动态失速过程实验研究。本研究的重点是详细测量机翼前后缘附近的非定常分离流。使用粒子图像测速技术进行测量。该技术提供了翼型翼展中部不同时刻的二维速度场和相关的涡量场。在前缘附近，由于货车Dommelen和Shen型分离和局部涡量积累，出现了大的涡结构。这些涡与反向边界层涡的相互作用引起二次流分离和二次涡的形成。这种反向旋转涡对的相互诱导最终导致动态失速涡从前缘区域的喷射过程。研究发现，后缘流场对动态失速过程仅起次要作用。
The dynamic stall process of an NACA 0012 airfoil undergoing a constant-rate pitching-up motion is studied experimentally in a water towing tank facility. This study focuses on the detailed measurement of the unsteady separated flow in the vicinity of the leading and trailing edges of the airfoil. The measurements are carried out using the particle image velocimetry technique. This technique provides the two-dimensional velocity and associated vorticity fields, at various instants in time, in the midspan of the airfoil. Near the leading edge, large vortical structures emerge as a consequence of van Dommelen and Shen type separation and a local vorticity accumulation. The interaction of these vortices with the reversing boundary-layer vorticity initiates a secondary flow separation and the formation of a secondary vortex. The mutual induction of this counter-rotating vortex pair eventually leads to the ejection process of the dynamic stall vortex from the leading-edge region. It is found that the trailing-edge flowfield only plays a secondary role on the dynamic stall process.