论文标题
Dusuk Reynolds Sayili Akislarda Kanat Uzerinde Kararsiz Aerodinamigin Incelenmesi
Dusuk Reynolds Sayili akislarda kanat uzerinde kararsiz aerodinamigin incelenmesi
论文作者
论文摘要
最近，在低雷诺（RE）数量下运行的无人机，微型航空车，鸟类和昆虫有关的研究数量最近迅速增加。 In this thesis, unsteady aerodynamics of low Reynolds number flows (Re=25000, 50000 and 75000) on NACA4412 airfoil shaped wing which is mainly used in wind turbines and micro air vehicles and operates at low Reynolds numbers and has aspect ratio of 1 (AR=1) was investigated by means of numerous experimental analyses at various angles of attack changing from 0° to 45°.由于获得的力测量结果，最大升力系数和失速角分别确定为1.19、1.21、1.24和39°，38°，37°，37°，RE = 25000、50000和75000。用烟雾和油可视化流量，在机翼上的不同平面（z/s = +0.4，+0.2，+0.1，0，-0.1，-0.2）进行速度分布实验。此外，确定了尖端涡旋对机翼的影响。在机翼的尖端观察到尖端涡流以低攻击角度观察到，并通过尾流区域发展在机翼上，随着攻击角的增加和这些涡流对机翼的影响增加。可以看出，尖端涡旋导致尾流区域的压力差并移动到跨度方向，并且这种情况导致分离气泡减少，这是在低RE数字下发生的，并增加了失速角度。此外，由于尖端涡流，流动条件变得更稳定。
The number of studies related to unmanned air vehicles (UAV), micro air vehicles (MAV), wind turbines, birds and insects which operate at low Reynolds (Re) numbers have rapidly increased, recently. In this thesis, unsteady aerodynamics of low Reynolds number flows (Re=25000, 50000 and 75000) on NACA4412 airfoil shaped wing which is mainly used in wind turbines and micro air vehicles and operates at low Reynolds numbers and has aspect ratio of 1 (AR=1) was investigated by means of numerous experimental analyses at various angles of attack changing from 0° to 45°. Due to the obtained force measurement results, maximum lift coefficients and stall angles were determined as 1.19, 1.21, 1.24 and 39°, 38°, 37° for Re=25000, 50000 and 75000, respectively. Flow visualization with smoke-wire and oil, velocity distribution experiments were conducted at different planes (z/s= +0.4, +0.2, +0.1, 0, -0.1, -0.2) on the wing. Furthermore, the effects of tip vortices on the wing were determined. The tip vortices were observed at the tip of the wing at low angles of attack and developed through the wake region moved on the wing horizontally with increasing angle of attack and effect of these vortices on the wing increased. It was seen that the tip vortices caused to pressure differences in the wake region and moved to the spanwise direction and this situation led to decrease separation bubble, which is occurred at low Re numbers, and increase stall angle. Additionally, flow condition became steadier due to the tip vortices.
