Effects of the Engine Propulsion on Flutter Boundary of High-Aspect-Ratio Wing

An interaction method of CFD combined with geometrically exact beam based on Simo theory for fluid-structure interaction (FSI) is proposed to analyze the effects of engine propulsion on stability of very flexible structures, which have been discussed via the existing linear aerodynamic forces models. Aiming at the high-aspect-ratio wing with engines, the mentioned method is adopted to evaluate the wing flutter boundary with variations of the parameters, including propulsion, bending-torsion stiffness ratio, engine mass, and engine position, where the lateral follower force and concentrated mass are simulated as the engine thrust and nacelle mass respectively. The geometrically exact beam based on Simo theory for nonlinear structure is coupled with Reynold-averaged Navier-Stokes aerodynamic equation to construct the nonlinear aeroelastic model used in numerical simulation of the high-aspect-ratio flexible wing. The nonlinear coupling of both structure and flow is considered in the aeroelastic model. The numerical results show that the engine propulsion has remarkable influence on the stability performance of the wing, and the influence is determined greatly by the mentioned parameters. The aerodynamic stability can be improved by such configurations as installation of the engine close to the wing root and the leading edge, and reduction of the bending-torsion stiffness ratio. It is necessary to consider the engine propulsion and its affiliated parameters in aerodynamic design or analysis of the flexible wing with engine mounted. © 2019, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.