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.