Universal Parameterization Technique for Airfoils

Source abstract

Airfoils are frequently designed using empirical knowledge and practical aeromodelling experience. In many cases, essential airfoil data exists only as discrete coordinate points obtained from scanned drawings or digitized outlines. Without a parametric representation, such airfoils are challenging to analyze, optimize, or reproduce during computational fluid dynamics simulations. Motivated by the need for a universal parameterization method that can express manually designed airfoils through a consistent set of mathematical functions or parameters, a new airfoil parameterization technique based on available coordinate data is proposed in this work. The proposed method is based on the least squares error approach and is applicable to any airfoil type, making it simple, versatile, and practical. The methodology is demonstrated on a variety of airfoils including natural laminar flow (NLF) airfoil, where the reconstructed geometry is compared against the original shape. Flow simulations were then carried out on the reconstructed NLF airfoils using an in-house compressible flow solver, and the results were validated with experimental data. A close agreement between both sets of results confirms the accuracy and effectiveness of the proposed method. Additionally, the study examines how variations in airfoil curvature influence the pressure gradient variation on the airfoil surfaces and corresponding effects on the flow separation as a function of the angle of attack.