Keywords

B-splines, airfoil parameterization, Bezier, Kulfan, Class Shape Transformation, PARSEC, NACA, airfoil optimization, CST

Abstract

In this paper, we apply well-known techniques for parametric curves to the definition and deformation of airfoil sections. While it has already been shown that many versions of Kulfan’s Class Shape Transformation (CST) are exactly equivalent to Bézier curves, we show here that all NACA 4-digit thickness distributions and the PARSEC parametrization of Sobiezcky are also higher-order Bézier curves. As with CST, Béziers and B-Splines provide direct control over aerodynamically meaningful features such as nose radius and boat-tail angle, but also provide more a intuitive parametrization of the rest of the airfoil surface. We show the efficacy of B-Spline-based parametrizations for approximating airfoil coordinates and for clean-sheet airfoil design. Finally, we show that this parametrization is ideally suited for progressive design.

Original Publication Citation

Rajnarayan, D., Ning, A., and Mehr, J., “Universal Airfoil Parametrization Using B-Splines,” AIAA Multidisciplinary Analysis and Optimization Conference, Atlanta, GA, Jun. 2018. doi:10.2514/6.2018-3949