High-fidelity Flutter Analysis of a Re-usable Launch Demonstrator with Wing-tip Vertical Tails

Through funding from the Air Force Research Laboratory, a wing tip-tail configuration for a future re-usable launch vehicle demonstrator was designed, structurally-sized through finite element based approaches, and then analyzed for aeroelastic performance. A time- domain flutter analysis of the tip-tail configuration was conducted with a CFD-based aeroelastic analysis capability, utilizing in-house CFD and FEM-based structural analysis tools integrated with the MultiDisciplinary Computing Enviroment (MDICE). The flutter boundary was computed by varying the altitude at several Mach numbers, until the structural response became unstable. The flutter solutions were obtained by first performing a rigid CFD solution, followed by a static aeroelastic CFD solution, and then proceeding to a transient simulation in which structural response was monitored for amplitude decay or growth. The CFD-based flutter results showed good agreement with linear aeroelastic analysis in terms of the flutter mechanism involved and the flutter frequencies. At subsonic Mach numbers agreement between linear and CFD-based results was also good, though in the transonic region, CFD results predicted a clear dip in flutter dynamic pressure which linear aeroelastic analysis failed to capture.