Coupling of Rotorcraft Elastic Fuselage with CFD

Accurate prediction of aeroelastic coupling between rotor wake and structure remains a key challenge to the development of advanced rotorcraft. Limitations of existing analysis tools to predict such aeroelastic interactions, notably empennage buffeting effects, have resulted in costly late-cycle design changes in multiple rotorcraft development programs, including the UH-60A and AH-64A. Aeromechanical phenomena involving interactions of the fuselage and rotor wake are complex, interdisciplinary, and three-dimensional in nature. For this reason, full vehicle CFD/CSD coupled analysis is essential to accurately capture the mutually dependent interactions between the aerodynamic loads and the aeroelastic response associated with these phenomena. The current state-of-the-art in rotorcraft analysis involves CFD/CSD coupled analysis of aeroelastic rotors and wings, but rigid representations of the fuselage and empennage structures (Ref. 1). To address this limitation, an elastic fuselage coupling capability was developed using RCAS and FUN3D. The elastic fuselage CFD/CSD interface has been successfully tested for several demonstration cases and one validation case.