In this paper, we study the aeroelastic behavior of a hovering bat using a three-dimensional variational fluid-flexible multibody framework. The aeroelastic framework consists of solving the coupled nonlinear interactions of flexible multiple components of the bat wing with the unsteady aerodynamics. To begin, we carry out the mesh convergence and compare the results of the presented formulation with the previous works on a flexible two-dimensional membrane subjected to low Reynolds number flow. We investigate the flapping dynamics of a full-scale bat using wing geometry and physical properties similar to the Pallas' long tongued bat Glossophaga soricina. The aeroelastic flexibility of the wing varies along its span and chord tending to a realistic bat wing, in contrast to the wing with uniform flexibility. We find that the flexible wings generate more unsteady lift compared to the rigid counterpart owing to the high wing-tip velocity due to the elastic deformation of the wings. Furthermore, we examine the time-varying vortex patterns and compare them with the experimental observations. We consider the effect of the anisotropic flexibility of the bone fingers and wing membranes on the aerodynamic lift as well as the vortex patterns generated by the flapping mechanism. Insights gained from the present study will be beneficial to develop novel designs for enhancing the maneuverability and flight agility of next-generation engineered flying vehicles (e.g., drones and micro-air vehicles) at low Reynolds number.
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