Airfoils are widely used in fluid flow applications such as aircraft, vehicles, and particularly in the blades of wind turbines, where aerodynamic efficiency plays a key role in enhancing performance and supporting sustainability. In this study, experimental investigations were carried out on two airfoil profiles commonly used in Darieus type vertical axis wind turbine applications: NACA 0015 and NACA 2415. The experiments are performed in two main parts: aerodynamic force measurements and surface oil flow visualization. In the first part, the aerodynamic performance of both airfoils is analyzed under two main configurations: the baseline model without guide vanes, and modified setups incorporating guide vanes with arc lengths increasing in 10° increments, up to a maximum of 50°. The effects of guide vane integration on the lift and drag characteristics are evaluated and compared. Graphs showing the variation of lift coefficient (CL) and drag coefficient (CD) with angle of attack (AoA) are provided for each case and for multiple freestream velocities. These results aim to highlight the influence of guide vane implementation on aerodynamic force generation and overall performance enhancement.
Alper Burgaç (Wed,) studied this question.