Transonic Aeroelastic Instability Suppression for a Swept Wing by Targeted Energy Transfer

Targeted energy transfer is studied as a means for suppression of transonic aeroelastic instabilities of a wind-tunnel swept wing, with a focus on designing a lightweight nonlinear energy sink that improves the critical flutter condition. The aeroelastic response modes of the wing with a nonlinear energy sink coupled to the tip are identified and tested for robustness using a medium-fidelity computational aeroelasticity model, and confirm that robust suppression of transonic aeroelastic instabilities is achievable. Accordingly, a nonlinear energy sink is designed based on a parametric study, and its transonic aeroelastic effects are studied using medium- and high-fidelity models. The results of both models indicate an improvement in stability over a broad range of conditions; the high-fidelity model predicts an approximately 40% increase in the dynamic pressure at the critical stability condition. Finally, a prototype winglet-mounted nonlinear energy sink is modeled to examine its aeroelastic effects. The results show that the nonlinear-energy-sink design is robust, but the winglet design plays a critical role that must be considered in the overall effect.