Unraveling the Complexity of Flapping Flight in Bats via High-Fidelity Fluid-Structure Interaction Modeling

Bats are amongst the most agile of natural flyers, and this agility can be attributed to the anatomy and kinematics of their wings. The wing consists of a highly elastic membrane stretched upon a skeleton with multiple joints, and the degree of articulation in the bat wing is incomparable amongst extant natural flyers, allowing for highly complex maneuvers. Previous studies have noted a high degree of dimensionality in the wing joint kinematics across bat species and flight conditions, and understanding this complexity and its implications for aerodynamics and aerodynamic force generation could be useful in developing bat-inspired micro aerial vehicles. In this work, we use modal decomposition to extract the spatio-temporal patterns from a collection of experimentally measured joint kinematics for different bat species and flight conditions. The extracted patterns are used to develop a data-driven model to generate representative joint kinematics for various flight conditions. The model serves as input to our coupled fluid-structure interaction solver, ViCar3D, and the force partitioning method (FPM) to quantify the role of wing kinematics and vortex dynamics on the aerodynamic forces in bat flight. By combining modal decomposition, data-driven modeling, fluid-structure interaction, and force partitioning techniques, our research aims to deepen our understanding of bat flight mechanics and pave the way for developing advanced biomimetic micro aerial vehicles.