Flutter of Highly Flexible Swept Wings

Novel aircraft designs typically have slender, lightweight wings that are more flexible than ever before, introducing new aeroelastic behaviors driven by large elastic deformations. Swept wings present unique aeroelastic characteristics due to their inherent bending-torsion coupling, which exists even in their undeformed state. When combined with large deformations, this coupling can significantly impact aeroelastic responses and alter stability boundaries.

The seminar will present a combined computational and experimental study of very flexible swept wings. Wind-tunnel tests were performed on two wing models, backward-swept by 10° and 20°, each in two tip-weight configurations (leading edge and trailing edge). These setups allowed separate investigations of swept-wing aerodynamic effects and elastic mode-coupling effects on the aeroelastic response and stability. The study presents a comprehensive investigation of the static response, flutter onset, and limit-cycle oscillations (LCOs). Data analysis reveals amplitude-dependent super- and sub-harmonic content, driven by different sources of nonlinearity in the system (namely, structural and aerodynamic).
Here is a 20-second teaser of a representative LCO case. We’ll conclude with implications for prediction, testing, and design of highly flexible wings.

Bar Revivo is a Mechanical Engineering master’s student analyzing very flexible swept wings through experiments under the supervision of Prof. Daniella Raveh.