Numerical analysis of the influence of airfoil geometry on aerodynamic performance at low Reynolds numbers

Abstract The development of small-scale horizontal-axis wind turbines (HAWTs) operating at low Reynolds numbers has recently garnered significant interest, particularly for applications in regions with low wind speeds. This study introduces an airfoil inspired by the morphology of a banana leaf stalk, which has been modified in terms of thickness and camber to enhance aerodynamic performance. Using the Blade Element Momentum (BEM) method, simulations were conducted at three Reynolds numbers: 30,000, 60,000, and 90,000. Performance metrics included lift coefficient (Cl), drag coefficient (Cd), and the lift-to-drag ratio (Cl/Cd). The modified airfoil was compared against the original design and several previously studied airfoils. Results showed that the modified airfoil outperformed the original across all Reynolds numbers. Specifically, Cl increased by 2.77% at Re = 30,000 and 0.88% at Re = 60,000, while it decreased slightly by 4.01% at Re = 90,000. In contrast, Cd was consistently lower for the modified airfoil, with reductions of 8.37%, 2.90%, and 8.02%, respectively. The Cl/Cd ratio improved significantly, with increases of 65.43%, 165.16%, and 145.41% across the three Reynolds numbers. These findings demonstrate that dimensional modifications can significantly impact airfoil performance and that the banana leaf-inspired design provides superior aerodynamic characteristics compared to standard airfoils at low Reynolds numbers.