A computational aeroelasticity framework for analyzing flapping wings

Flexible flapping wings have garnered a large amount of attention within the micro aerial vehicle (MAV) community: a critical component of MAV flight is the coupling of aerodynamics and structural dynamics. This dissertation presents a computational approach for simulating beam/shell-like wing structures flapping in incompressible flow at low Reynolds numbers in both hover and forward flight. Several nonlinear structural solutions of variable fidelity are coupled to an in-house developed pressure-based Navier-Stokes solution in a partitioned framework in which the nonlinear partial differential equations modeling the dynamic behavior of the fluid and the structure are solved independently with boundary information shared between each other.;In the initial part of dissertation, the development of a nonlinear structural dynamics solution suitable for flapping wings using the co-rotational approach is discussed. Next, the development of a suite of computational aeroelastic solutions is discussed. Verification and partial validation studies are presented for both the structural dynamics and the aeroelastic solvers using different wing configurations.;Case studies are presented for three different flexible wing configurations: rectangular wings with pure prescribed plunge motion, an elliptic wing with pure prescribed flap rotation, and a rectangular wing also prescribed with pure flap rotation. Numerical studies of the plunging wings showed that within the range of non-dimensional parameters considered, only a limited amount of spanwise flexibility is favorable for thrust generation. It was found that in the case of the most flexible plunging wing configuration, the instantaneous angle of attack at most sections along the wing span decreased relative to other wings of lower flexibility. This was identified as being responsible for the decrease in the aerodynamic forces generated. Further, issues related to coupling strategies, fluid physics associated with rigid and flexible wings, and phase lag between prescribed motion and response were carefully examined.;Preliminary aeroelastic studies on the rectangular and elliptic flapping configurations indicated that within the range of parameters considered, aerodynamic forces could be enhanced due to wing flexibility.;The nonlinear aeroelastic framework developed will enable comprehensive analysis of flapping wings in support of future experimental tests and ultimately lead to identification of new MAV flapping wing concepts.