Two-dimensional airfoil shape optimization for airfoils at low speeds

This paper presents a fast methodology for the design of two-dimensional low-speed airfoils. We propose a methodology in which the design process starts from an already known airfoil or from a new defined airfoil by imposing some basic geometrical characteristics, such as: the airfoil’s radius at the leading edge, the maximum height of the airfoil’s lower and upper sides, the slopes of the airfoil’s defining curves at the trailing edge and the trailing edge gaps. Based on the above initial geometry the airfoil shape is further parameterized by use of Bezier or Bspline curves, the relative merit of the two types of parameterization is carefully analyzed and exemplified in the results section. The control points of the defining curves can be used to optimize the shape of the airfoil. The Xfoil flow solver was used for the aerodynamical calculations, and Matlab’s fmincon was used as the optimizer.