Laminar airfoil modification attaining optimum drag reduction by use of airfoil morphing

In this paper, the effectiveness of morphing a laminar airfoil's leading edge through deformation in order to reduce the drag at the offdesign angle of attack is investigated. The configuration of the airfoil was deformed under the structural restriction that the leading edge is deformed while maintaining both the girth of the deformed part and the configuration of the wing box. The NACA63₁-012 laminar airfoil was chosen as the baseline airfoil. The Reynolds number based on the baseline airfoil chord was Re_c = 3 × 10⁶. Aerodynamic characteristics of the baseline and deformed airfoils have been investigated using a viscous-inviscid interaction method. It is shown that the leadingedge deformation is effective in reducing the drag at the offdesign angle of attack, in comparison with the baseline airfoil. The transition point has been estimated, using a numerical method based on a linear stability theory. The deformation is an effective means to move the transition point aft on the airfoil, and the extension of the laminar flow area results in a reduction in the drag at the offdesign angle of attack. 2010.