Integrated Theoretical and CFD Study on the Aerodynamic Behaviour of a Horizontal Axis Wind Turbine

Abstract

Wind energy is among the most promising renewable resources for sustainable electricity generation, and Horizontal Axis Wind Turbines (HAWTs) are extensively adopted because of their superior aerodynamic efficiency and dependable operation. This work presents a combined theoretical and Computational Fluid Dynamics (CFD) investigation of the aerodynamic performance of a large-scale HAWT with a rotor radius of 40 m. The main aim is to assess key performance indicators, including the power coefficient (Cp), torque, tip speed ratio (TSR), as well as velocity and pressure distributions, while validating analytical predictions through CFD simulations. The theoretical framework is developed using momentum theory and Betz’s limit to estimate the maximum achievable wind power extraction and to determine turbine performance characteristics. These analytical outcomes serve as a reference for comparison with numerical findings. CFD simulations are conducted in ANSYS Fluent, where turbine blades based on the NACA 4412 aerofoil are modelled under steady wind conditions. The SST k–ω turbulence model is applied to effectively capture boundary layer phenomena, pressure gradients, and three-dimensional flow behaviour around the blades. The CFD results provide detailed insights into flow patterns, highlighting increased velocity near the blade tip and clear pressure differences between the suction and pressure surfaces. Overall, strong agreement is obtained between theoretical and CFD predictions, with deviations remaining within acceptable ranges. The estimated power output and torque values further confirm the turbine’s efficient aerodynamic performance. This study underscores that integrating theoretical analysis with CFD simulations offers a robust and comprehensive methodology for wind turbine aerodynamic evaluation, supporting design optimization and performance improvement of large-scale HAWTs.