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通过数值求解非定常不可压N-S方程,研究微型飞机的小展弦比机翼在低Reynolds数下的流动特征。研究对象是展弦比为1.33,截面形状为E-174翼型的椭圆形机翼。数值模拟的Re=1×104,迎角为0°～45°。结果表明:从0°到10°迎角,机翼附近的流场是两侧对称的;迎角大于11°,流动变为两侧不对称。这个现象的出现是由于翼尖涡和机翼上表面的二次分离涡相互作用,使翼尖涡发生失稳。由于粘性作用,在整个迎角范围内气流发生分离。迎角小于33°,分离涡从机翼的上表面不断脱落;迎角大于33°,分离涡保持在机翼的背风面,形成驻涡现象。
The numerical simulation of unsteady incompressible Navier-Stokes equations is used to study the flow characteristics of small aspect ratio airfoils under low Reynolds number. The object of study was an elliptical wing with an aspect ratio of 1.33 and a cross-section of E-174 airfoil. Re = 1 × 104 of numerical simulation, angle of attack is 0 ° ~ 45 °. The results show that from 0 ° to 10 ° angle of attack, the flow field near the wing is symmetrical on both sides; the angle of attack is greater than 11 ° and the flow becomes asymmetrical on both sides. The appearance of this phenomenon is that the tip vortex vortex instability due to the interaction between the tip vortex and the secondary separation vortex on the upper surface of the wing. Airflow separates throughout the angle of attack due to the sticking effect. Angle of attack is less than 33 °, the separation of vortex from the upper surface of the wing constantly falling; angle of attack greater than 33 °, the separation of vortex to maintain the wing leeward to form a vortex in the phenomenon.