Collaborative Research: Decoding the Aero-Structural Dynamics of Feathered Wings in Flapping Flight via Computational Models

Feathered wings are a fascinating part of bird flight, yet they are not well understood. These wings have unique properties, from tiny barbicels that maintain structural integrity to individual feathers that change position, shape, and alignment. Flight feathers are both flexible and strong, and act individually or together depending on the flight situation.

The close arrangement of feathers enables complex airflows between them, affecting aerodynamic force generation and feather deformation. However, our knowledge of these dynamics is limited. This project aims to investigate the unique properties of feathers and feathered wings that enhance flight capabilities, including their porosity and deformability, and their ability to change shape during flapping.

The research combines experiments on isolated feathers, groups of feathers, computational models, and live bird observations to study this complex problem. The fascination and intrigue evoked by bird flight and the multi-modal research approach adopted here will be leveraged for outreach to undergraduate and K-12 students. The students and trainees involved in this project will become part of a new generation of scientists and engineers capable of applying computational and experimental methods across disciplines to tackle complex problems.

The goals of this project are to: (1) investigate the aerodynamics and aero-structural dynamics of individual feathers; (2) study the interactional flow effects in multi-feather configurations; and (3) explore the aerodynamics of flapping flight with feathered wing-inspired models. First-of-their-kind computational models will be developed to incorporate not only the complex vortex dominated flows generated by feathers but also the aero-structural deformations and feather permeability.

These computational models will be parameterized by structural testing and wind-tunnel studies of feathers as well as flying birds. The simulations will use innovative modeling approaches and efficient computational algorithms to bridge the very large range of scales that are encountered in this multi-physics problem. Micro-computed tomography imaging, micro-tensile testing, and wind-tunnel recordings of the aeroelasticity of feathers will provide key data for input and comparison with the simulations.

The computational models of multi-feathered flapping wings parameterized from feather kinematics extracted from birds in flapping flight will significantly advance understanding of the function of this unique and intriguing flight “device.” The findings could improve designs for drones, making them lighter, quieter, and more efficient. The research could also lead to better understanding of flow over porous surfaces, benefiting various fields like aeronautics, biomedicine, and engineering.

Finally, this research will enable exceptional educational and training opportunities for students at the intersection of biology and engineering.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.