Design of a biomimetic wing from maple samara and investigation of the aerodynamic performance

Abstract

The morphological structure and airborne behavior of maple samaras have attracted increasing attention due to their potential use in wind turbines and air vehicles. This study introduces a new methodology based on mathematical modeling to transfer the geometric structure of maple samaras to a virtual environment and presents an experimental and numerical investigation of the performance of a model wing designed with this method. Certain sections were taken along the structure of maple samaras, measurements were made, curves were obtained mathematically for each section, and these curves were transferred to a design program. A biomimetic three-dimensional model was generated by combining these curves. The mathematical modeling of these curves was obtained with certain degrees of expansion of the Fourier series. Experimental and numerical studies of the designed biomimetic model were performed at different free stream velocities and angles of attack. The trend of the lift coefficient curves indicated that the samara wing model has a larger range of angle of attack, up to 40°-45° without a stall, and the maximum lift to drag ratio (CL/CD) was obtained at 8° angle of attack. In addition, the present model showed more stable performance, and the lift and drag forces did not change as much as in conventional blades at varying free flow velocities. In the analysis results, the air flowing over the wing caused the formation of these vortices inside the ordered trough top structures of the model. These vortices, seen from the leading edge, are thought to play an effective role in the lift coefficient of the biomimetic samara model.