Aerodynamic optimization design of airfoil based on directly manipulated FFD technique

The method of applying direct manipulated FFD (DFFD) technique into aerodynamic shape optimization has been proposed and researched. Due to the disadvantage of the original FFD method within which the geometrical manipulation is not direct and intuitive, the DFFD approach has been developed by solving each displacement of the FFD control points with some specified geometry points' movements, so that the deformation of the target geometry could be directly manipulated. Besides, it has been illustrated that by DFFD method a relatively small number of design variables together with high order FFD control frame could be accomplished. The study cases has shown that applying this method in aerodynamic shape optimization of airfoil for drag reduction is of good feasibility and result, and could be coupled with effective geometrical constraints like airfoil thickness.