Aerodynamic investigations toward an adaptive airfoil for a transonic transport aircraft

Abstract

Drag reduction and the extension of the flight region with high aerodynamic efficiency for transonic airfoils has been investigated by applying the idea of an adaptive airfoil. With the aid of the elliptic continuation method, a basic airfoil has been optimized with regard to shock-free pressure distributions for three different flow conditions (A/,c/). The three resulting airfoils, representing operating points of an adaptive airfoil, have been investigated numerically and in wind tunnel tests. The results indicate that high aerodynamic efficiencies are connected with pressure distributions having already weak shock waves. Furthermore, the anticipated extension of the flight region with high aerodynamic efficiency by applying an adaptive airfoil could not be verified for all flight conditions.