Influence of Aerodynamic Interaction Between Rotor and Wing Upon Whirl Flutter Stability in a Tiltrotor Aircraft

摘要

Aeroelastic stability analysis is conducted regarding a tiltrotor aircraft with several aerodynamic models in time and frequency domains. Two significant structural features, which are the rotor blade flexibility and wing sweep, are considered. Three different aerodynamic models, a normal, Greenberg's quasi-steady, and full unsteady aerodynamic model, are used for the rotor. The two-dimensional strip theory is considered for the wing. The influence of the wing aerodynamics and swept effect is conducted, and the resulting damping of the wing vertical mode is compared with and without wing aerodynamics and sweep. The wing aerodynamics forces the stability boundary increased due to aerodynamic damping, but on the other hand the boundary is decreased with sweep of the wing. The unsteady aerodynamics is also adopted and compared with the previous results by quasi-steady aerodynamics. The highest flutter boundary is obtained by the full unsteady aerodynamics.