A numerical framework for isotropic and anisotropic flexible flapping wing aerodynamics and aeroelasticity

A numerical framework is presented to simulate rigid and flexible flapping wings. The fluid-structure interaction is realized by coupling a Navier-Stokes solver to a geometrically nonlinear co-rotational structural solver. In the coupled fluid-structure interaction interface the aerodynamic loading and deformed wing surface are shared by two solvers within each time step. A remeshing method based on radial basis function is implemented to handle large deformations, preserve grid quality, and execute economically. Flexible flapping wing operating in both vacuum and air is considered to shed light on inertial and aerodynamic loading-induced shape deformation. Impacts of flapping isotropic wing with single degree of freedom rotation on aerodynamic force generation are presented for Re= 1.5×10³ and k= 0.56. The results indicate: 1) the flexibility-induced pitching angle promotes thrust generation, and 2) the increase of wing velocity due to large bending motion enhances aerodynamic force by increasing pressure differences. For a wing of anisotropic mechanical properties, highly three-dimensional wing deformation is observed when the wing accelerates or decelerates in absent of aerodynamic loadings.