Numerical Simulation of the Flapping Eagle, Owl and S1223 Airfoils

In this study, the aerodynamic performance of the flapping owl, eagle and S1223 airfoils was investigated numerically using ANSYS Fluent commercial CFD code. The study was carried out by solving Reynolds Averaged Navier Stoke (RANS) equations where the turbulence was modeled by k-Epsilon turbulence model. The moving mesh strategy was adapted for the airfoil flapping. The numerical results were obtained for a Reynolds number of
$7\times 10^{5}$
and a flapping rate of
$\mp 0. 5\frac{rad}{s}$
. The results were presented in terms of pressure contours, streamlines, time history fluctuation of the lift and drag coefficients and aerodynamic efficiency. The downstroke and upstroke pressure contours and streamlines show similar aerodynamic behavior for the studied airfoils. The only differences are the size and the location of vortices. In comparison to the S1223 airfoil, the results showed that the eagle and owl airfoils generated more lift during the downstroke mode and less lift during upstroke mode. In terms of aerodynamic efficiency, eagle's airfoil generates the highest lift to drag ratio followed by S1223 airfoil. The obtained results showed good agreement with the published results in terms of the time history fluctuation trend for the lift and drag coefficients.