Computational and Experimental Investigation of Limit Cycle Oscillations of Nonlinear Aeroelastic Systems

A wide variety of pathologies, such as store-induced limit-cycle oscillations, have been observed on high-performance aircraft and have been attributed to transient nonlinear aeroelastic effects. Ignoring the nonlinearity of the structure or the aerodynamics will lead to inaccurate prediction of these nonlinear aeroelastic phenomena. The current paper presents the development and representative results of a high-fidelity multidisciplinary analysis tool that accurately predicts limit-cycle oscillations (LCOs) of an aeroelastic system with combined structural and aerodynamic nonlinearities. Wind-tunnel measurements have been carried out to validate the findings of the investigation. The current investigation concentrates on the prediction of the critical physical terms that dominate the mechanism of LCO. The aeroelastic computations predict LCO amplitudes and frequencies in very close agreement with the experimental data. The results emphasize the importance of modeling the nonlinearities of both the fluid and structure for the accurate prediction of LCO for nonlinear aeroelastic systems.