Structure and induced drag of a tip vortex
Structure and induced drag of a tip vortex
复制标题
DOI：
10.2514/1.2707
复制
发表时间：
2004-09-01
影响因子：
2.2
通讯作者：
Kafyeke, F
中科院分区：
文献类型：
--
作者：
Birch, D;Lee, T;Kafyeke, F
本文用七孔压力探针在Re = 2.01 × 10 ~（5）下研究了NACA 0015矩形翼型和高升力曲面翼型近尾迹区叶尖涡的三维流动结构。升力诱导阻力是根据涡量计算的，并与力平衡数据进行了比较。对于这两种试验翼型，涡流强度在后缘后立即达到最大值，并在下游两个弦长处几乎保持不变。随着翼型迎角的增加，升力的增加导致涡强度和切向速度及涡量峰值基本呈线性增加，而涡半径对涡强度的依赖性不明显。取决于翼型的冲角，核心轴向速度可以是尾迹状或射流状。近轴对称叶尖涡内部区域的标准化环量呈现出普遍的或自相似的结构。然而，NACA 0015翼型的切向速度较小，但涡核直径与弧形翼型相似。
The three-dimensional flow structure of a tip vortex in the near wake of both a rectangular, square-tipped NACA 0015 airfoil and a high-lift cambered airfoil was investigated by using a seven-hole pressure probe at Re = 2.01 x 10(5). Lift-induced drag was computed based on vorticity and was compared with force-balance data. For both the airfoils tested, the vortex strength reached a maximum immediately behind the trailing edge and remained nearly constant up to two chord lengths downstream. As the airfoil incidence increased, the increase in the lift force resulted in a basically linear increase in the vortex strength and the peak values of the tangential velocity and vorticity, whereas the vortex radius did not appear to have a clear dependence on the vortex strength. Depending on the airfoil incidence, the core axial velocity could be wake-like or jet-like. The normalized circulation within the inner region of the nearly axisymmetric tip vortex exhibited a universal, or self-similar, structure. The NACA 0015 airfoil, however, possessed smaller tangential velocities but similar vortex core diameters compared to those of a cambered airfoil.