Rotorcraft Elastic Fuselage Coupling with CFD

Helicopter buffeting and other interactional rotorcraft vibration phenomena, occur as a result of mutually interacting airloads and structural motions from the rotor, hub, fuselage, and empennage. These phenomena are amenable to state-of-the-art analysis technology and addressing them is long overdue.Computational Fluid Dynamics (CFD) provides the highest fidelity for fluid physics while Computational Structural Dynamics (CSD) provides accurate elastic structure modeling. Combined, CFD/CSD coupled analysis is essential to representing the mutually dependent aeroelastic interactions associated with these phenomena. However, current coupling implementations are limited to rotors and wings, while the fuselage and empennage structures critical for prediction of interactional vibration phenomena are rigidly modeled. An opportunity exists to address this problem by expanding CFD/CSD analysis technology to include aeroelastic coupling of fuselage and empennage. This effort leverages existing CSD technology by utilizing the Rotorcraft Comprehensive Analysis System (RCAS) and CFD by utilizing CREATE-AV HELIOS and other CFD programs to focus development on the fluid structure interface (FSI). The main requirements of which are accurate recovery of deformations and conservation of total force and energy.Although this development targets interfacing CFD with RCAS, the developed FSI will be general and made available for integration into other structural dynamics programs.