Optimization of Low Reynolds number airfoil design using Full Inverse Design method

Abstract

This research study is aimed at designing an improved low Reynolds number airfoil from a baseline 4-digit NACA airfoil using the traditional Full Inverse Design method to maximize the lift-to-drag ratio, among others. XFOIL was used as an aerodynamic solver while XFLR5 v6.57 design and analysis software was employed for the design optimization. The NACA2408 airfoil was used as a reference airfoil for optimization due to its application in wings when long-endurance characteristics are desired. A newly-designed and novel airfoil, with a larger thickness and camber distribution compared to the baseline airfoil, is presented in this study. The new airfoil demonstrated up to 19.9% and 33% improvement in the lift coefficient and lift-to-drag ratio, respectively from reference airfoil results at Reynolds number of 3x106. The numerical results of the newly-designed airfoil were compared with the available results of ten selected standard airfoils and showed 18% and 32.5% general improvement in the lift coefficient and lift-to-drag ratio, respectively at the same Reynolds number. The optimized airfoil was further numerically tested with the computational fluid dynamics software, ANSYS FLUENT, and the results of the numerical simulations showed good agreement with XFLR5’s computationally obtained results.