QBlade-based aerodynamic investigation of NREL S823 and S815 airfoils under different Reynolds regimes

Department of Mechanical Engineering, Vardhaman College of Engineering, Kacharam, 501218 Telangana, India

^* Corresponding author: kanthala.umareddy@gmail.com

Published online: 7 January 2026

Abstract

The efficiency of lift-based wind turbines mainly depends on the selection of airfoils and its performance under various operating flow conditions. So, it is very important to study the airfoil performance, nothing but aerodynamic behaviour, under different flow conditions. Such kind of study is attempted in this work. For that, two airfoils viz., NREL S823 and NREL S815 were selected and analysed using the open source QBlade software, which built on XFOIL. The simulation is carried out under various Reynolds numbers (Re) fluctuating between 0.13×10⁵ to 0.26×10⁵. From the results, the various aerodynamic characteristics such as lift coefficient (CL), Sliding ratio also called as Lift to Drag ratio (CL/CD), along with Coefficient of Pressure (Cp) were analysed over a range of AoA (angle of attack) i.e., - 5° to 20°. The simulation results revealed that, the NREL S823 airfoil demonstrates greater CL value at lower Re numbers, making it appropriate choice for small-scale wind turbines, while S815 displays smoother stall characteristics and higher CL/CD values at higher Re, which is more required for medium scale wind turbines. Moreover, distribution in CP is a significant factor in deciding which airfoil to apply to the wind turbine designs, whether the design focus is upon the greatest possible operating stability or the ratio of lift to drag performance at variable aerodynamic load. The presented QBlade-based study helps to identify the impact of the Reynolds number on aerodynamic behaviour and offers comparative information on the suitability of the airfoils S823 and S815 in various applications in wind turbines.