Numerical Simulation Of The Pitching/plunging Coupling Oscillating Around A Two-dimensional Airfoil

Aeroelastic flutter involves the unfavorable interaction of aerodynamic, elastic, and inertia forces with structures and produces an unstable oscillation that often results in structural failure, so it's significant for the aircraft design. The inner cause of the flutter is the possibilities of the coupling of the structural modes, and the aerodynamic force is the out cause driving the coupling. On one hand, properly designing the structures of the craft can lower the coupling possibilities; on the other hand, the study of aerodynamics can avoid the adverse flutter or even uncouple the modes. It's high significant for applied projects to investigate the occurrence and development of flutter.Flutter is the nonlinear dynamical system steady problem in math. It has great significance not only in theory but also in structural and aerodynamic design of the aircraft to investigate the nonlinear characteristics of the dynamic system and the occurrence and development of unsteady.The pitching/plunging coupling oscillating around a two-dimensional airfoil is the basic flutter research model. This paper has studied the numerical simulation of the pitching/plunging coupling oscillating around a two-dimensional airfoil.Firstly, the unsteady aerodynamic force has been studied at different forced pitching/plunging conditions without considering the structural coupling. The pitching oscillating has been numerically simulated through solving the Euler/N-S equations in time domain, with the second order accuracy in time and space and a B-L turbulence model. The C type grid around the deforming airfoils is generated using the improved transfinite interpolation method. The results compare well with the public wind tunnel test data.Then, the unsteady aerodynamic and aeroelastic equations are solved in the time domain to investigate the pitching/plunging coupling oscillating around the airfoil under the unsteady aerodynamic force at different flight conditions. The response of unsteady aerodynamic force and structures has been calculated. The limit circle oscillation and the relationship between the flutter speed and Mach number have been studied. The computational results has shown, that with the relative speed increasing, the range of attack angle increases and the attenuation rate decreases; that the limit circle oscillation occurs when the relative speed increases to some point, whose swing increases with the relative speed increasing. The results compare well with the public data, which means the method used in the paper is feasible.Finally, we have summarized the whole paper and binged forward some works we should do next step.