1 Computational Modeling of Spanwise Flexibility Effects on

The implications of spanwise flexibility on flapping wing aerodynamics are investigated numerically for a rectangular wing in pure heave. A computational framework for fluid-structural interactions has been developed based on a direct coupling procedure between (i) a pressure-based finite-volume fluid flow solver based on the Navier-Stokes equations, and (ii) a quasi-3D finite element structural dynamics solver based on a geometrically nonlinear composite beam-like and linear plate-like formulations. The computational results are first correlated with available experimental data. It is shown that two key factors associated with spanwise wing deformation affect thrust generation, namely, in-phase motion between the wing tip and root, and the increased effective angle of attack of the deformed wing. If the wing motions resulting from both prescribed motion and deformation are correlated, the increased effective angle of attack at the tip could enhance the aerodynamic performance. If the flexibility is too high, then the wing tip and root could move in inconsistent directions, resulting in deteriorated aerodynamic performance. Nomenclature AR = aspect ratio = b2/