Tiltrotor Whirl-Flutter Assessment by Multifidelity Aerodynamic Models

This work evaluates the whirl flutter characteristics of a three-bladed stiff-inplane tiltrotor representative of the XV-15 equipped with Advanced Technology Blade (ATB) using the viscous vortex particle method, uniform inflow, and dynamic inflow in powered configuration. The open-source multibody code MBDyn is used to build, verify, and validate the aeroelastic model using uniform and dynamic inflow. At the same time, the vortex particle method is implemented in the open-source code DUST. The two solvers are coupled using the preCICE library. Results show that the vortex particle method and dynamic inflow well correlate, while the uniform inflow exhibits a more conservative behavior. Adding the effect of wing aerodynamics introduces a significant difference in the wing bending mode flutter trends where the vortex particle method predicts a lower damping for the entire flight envelope.