高速旋翼飞行器上使用正弦后缘叶片控制反向流动
Control of Reverse Flow on High-Speed Rotorcraft Using a Blade with a Sinusoidal Trailing Edge
- Indian Institute of Technology Kanpur（印度坎普尔理工学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过实验验证了正弦后缘叶片作为被动方法能有效控制高速旋翼飞行器后行桨叶的反向流动，显著减轻流动分离及相关问题，并消除俯仰力矩脉冲，且对正向流动影响最小。
AI中文摘要：
限制高速旋翼飞行器最大前飞速度的主要挑战之一是后行桨叶上反向流动的发展。在反向流动期间，尖锐的气动前缘处的流动分离导致负升力、高阻力、高俯仰力矩以及俯仰力矩脉冲。本研究在静态俯仰条件下，实验研究了正弦后缘作为被动方法控制反向流动的有效性。评估了三个NACA 0015二维叶片在反向和正向流动条件下的性能。一个具有直后缘的基准叶片和两个具有正弦后缘的改进叶片，其空间振幅分别为弦长的10%，波长分别为弦长的5%和10%。实验在基于弦长的雷诺数70000和140000下进行，包括平面粒子图像测速和气动载荷测量。研究表明，正弦后缘显著减轻了流动分离，在广泛的攻角范围内大幅减少了相关问题。俯仰力矩脉冲问题被消除。波长较低（弦长的5%）的正弦几何形状表现出相对更好的性能。此外，两种正弦几何形状对正向流动特性的影响最小。
英文摘要：
One of the main challenges limiting the maximum forward speed of high-speed rotorcraft is the development of reverse flow on retreating blades. Flow separation at the sharp aerodynamic leading edge during reverse flow leads to negative lift, high drag, high pitching moment, and a pitching moment impulse. The study experimentally investigates the effectiveness of a sinusoidal trailing edge as a passive method for the control of reverse flow, under static pitching conditions. Three NACA 0015 two-dimensional blades were evaluated under both reverse and forward flow conditions. A baseline blade with a straight trailing edge and two modified blades with sinusoidal trailing edges, each having a spatial amplitude of 10% of the chord and wavelengths of 5% and 10% of the chord, respectively. Experiments were conducted at chord-based Reynolds numbers of 70000 and 140000, consisting of planar Particle Image Velocimetry and aerodynamic load measurements. The study shows that a sinusoidal trailing edge significantly mitigates flow separation, leading to a large reduction in the associated problems over a wide range of angles of attack. The problem of pitching moment impulse is eliminated. The sinusoidal geometry with a lower wavelength of 5% of the chord shows comparatively better performance. Additionally, both sinusoidal geometries minimally affect the forward flow characteristics.
