A Parametric Study of Bionic Airfoil Based on Long-eared Owl Wing
As the bionic prototype,five feature points of the lower surface of the long-eared owl wing are extracted by using the reverse reconstruction technique.The B-spline curve is adopted to establish the bionic airfoil model.Three-dimensional viscous Reynolds-averaged Navier-Stokes equations and SST(shear stress transport) turbulence model coupled with Langtry-Menter transition model are solved to perform the orthogonal experiment.The effects of front arc curvature,leading edge thickness,leading edge angle,lower surface curvature and trailing edge thickness on the lift-drag ratio are investigated.Based on the orthogonal experiment results,an optimal bionic airfoil that suppressed effectively the flow separation under the higher angle of attack is obtained.The numerical results show that the leading edge thickness is the most important factor to influence the airfoil performance. The lift-drag ratio increases while the leading edge thickness is reduced.There are optimal lower surface curvature and trailing edge thickness for the maximum lift-drag ratio of the bionic airfoil.