Optimizing the Aerodynamic Efficiency of Different Airfoils by Altering Their Geometry at Low Reynolds Numbers

Abstract

Small wind turbines (SWTs) can generate sufficient electricity to meet the energy needs of developing countries. However, due to the airflow characteristics at low Reynolds numbers and associated issues, specific airfoil designs are crucial to define the blade geometry. In this study, the lift coefficient (CL), stall angle of attack (AoA), and lift-to-drag coefficient ratio (CL⁄CD) of S1048, S3021, and S5010 airfoils and then optimized shapes with various thickness-to-camber ratio percentages (t/c%) were analyzed using XFOIL software to optimize their suitability for SWT applications. The aerodynamic efficiency of the optimized airfoils in terms of CL, drag coefficient (CD), CL/CD, and stall AoA was evaluated across Reynolds numbers ranging from 50,000 to 500,000. The findings revealed that these modified airfoils exhibited peak CL⁄CD values surpassing those of their baseline airfoils for the Reynolds number range of 50,000–500,000. The magnitudes of these improvements varied for each airfoil and at different Reynolds numbers. Additionally, the geometric modifications in terms of t/c% applied to the S1048, S3021, and S5010 airfoils resulted in enhanced maximum CL and stall AoA across all analyzed Reynolds numbers.