Numerical Research on Segmented Flexible Airfoils Considering Fluid-structure Interaction

This paper investigated four kinds of segmented flexible airfoils with membrane material on the upper surface and rigid structure on the lower surface. Fluid-structure interaction method was adopted in the numerical simulation for the aerodynamic characteristics and response between flow field and structure of the segmented flexible airfoils. The research focuses on influence of flexible deformation on the lift and drag characteristics and the aerodynamic load distribution of four segmented flexible airfoils at Reynolds number of 1.35×105. The results show that the segmented flexible airfoils perform a higher maximum lift coefficient, and effectively delay the stall. At the higher angles of attack, the deformation of the flexible thin membrane could reduce the scale of the separation vortexes. Meanwhile the tiny vortex generated between the flexible segments with the effect called “Fluid Roller Bearing” would impel the separated boundary layer to reattach to the airfoil surface especially on the first half chord region. The three-segment flexible airfoil was proved to be the best airfoil among the four airfoils, which could increase the lift coefficient by 39% near the stall angle of attack compared with its rigid counterpart.