大后掠翼前缘涡对其颤振特性的影响

大迎角三角翼的前缘涡不仅可以改善其气动力特性,也会显著影响机翼的气动弹性特性.运用基于Euler方程的非定常气动力降阶模型(ROM)方法,耦合结构运动方程,在状态空间内建立了气动弹性分析模型,研究了70°削尖三角翼的大迎角颤振特性.研究结果显示前缘涡对该机翼颤振特性的影响不可忽略.颤振速度随迎角的增加而大幅降低,迎角α=20°时的颤振速度比α=0°时降低了22%.发现了颤振特性随迎角变化时出现的不连续现象,并揭示了该现象是由于系统颤振分支随着静态迎角的增加发生转移所致.

Effects of Leading-edge Vortex on Flutter Characteristics of High Sweep Angle Wing

The leading-edge vortex of delta wing can not only improve the wing's aerodynamic characteristics, but also affect its aeroelastic characteristics. By using unsteady aerodynamic reduced order models(ROM) based on Euler codes and coupling with structural motion equations, an aeroelastic analysis model is constructed in state-space. The flutter characteristics of a 70° cropped delta wing at high angles of attack are studied. The results show that the leading-edge vortex has a significant impact on the flutter characteristics of that delta wing. The flutter speed greatly reduces with the increasing angle of attack, which shows a 22% decrease at α=20° compared with that at α=0°. The flutter branch may change with the increasing steady angle of attack, which leads to a discontinuity in flutter characteristics.