大攻角地效翼非定常流动实验研究

大攻角地效翼非定常流动研究对大攻角地效翼非定常空气动力特性和流动控制具有重要的意义。对攻角为18°的NACA0012地效翼在模型风洞中进行实验，利用三维热线风速仪对地效翼后缘附近尾迹区内测点的速度脉动进行采样，分析不同飞行高度下大攻角地效翼的非定常流动特性。结果表明：地面效应下，大攻角地效翼后缘涡系形成位置后移；随着地效翼高度的降低，非定常流动的脉动频域宽度减小，速度脉动特征频率减小。

Experimental Study on Unsteady Flow of Wing-in-ground Effect at High Angle of Attack

Studying on unsteady flow of wing-in-ground effect at high angle of attack is of important significance for the aerodynamic characteristics and control of unsteady flow. Wing-in-ground effect of NACA0012 at angle of attack of 18° was tested in a model wind tunnel. The velocity fluctuations in wake near the trailing edge were captured by 3D CTA. Unsteady flow of wing-iwground effect in different flight height was analyzed based on the test results. It is shown that vortices near trailing edge of wing in ground effect at high angle of attack are shifted backwards in ground effect. With the decrease of the flight height, both the frequency and the bandwidth of velocity fluctuations are decreased.