Non-Linear Aeroelasticity - Time and Frequency Domain

Kurzfassung

Flutter of aeroelastic systems with discrete structural nonlinearities is computed in the time domain and compared with frequency domain results. The simulation approach is based on the coupling of the discretized fluid and structural equations. Embedded in an effective procedure to determine complete flutter boundaries (bifurcation diagrams), the method is employed to investigate the flutter stability of an airfoil with a trailing edge flap for hardening and softening stiffness characteristics in the control mechanism. For comparison the aerodynamic forces are determined by the classical linear unsteady thin airfoil theory for incompressible inviscid flow and by a CFD method to solve the Euler equations. The typical flutter behavior of the system is described and explained by comparing it with the flutter properties of a linear reference model. The results validate the simulation method and provide a deeper insight into the nonlinear flutter mechanisms of airfoils with control surfaces.