ABSTRACT The increasing demand for energy in daily life and the finite nature of fossil fuel reserves have driven researchers worldwide to explore renewable energy sources such as wind energy. To optimize the performance and minimize energy losses in vertical wind turbines, parameters such as the airfoil's angle of attack, as well as the horizontal and vertical distances between the cylinder and the airfoil, must be adjusted to maximize aerodynamic efficiency and minimize entropy generation. Additionally, parameters such as the turbulent kinetic energy and Kolmogorov length scale are pivotal in engineering design. Each section of a wind turbine blade can be modeled as an airfoil, while the internal part of the main shaft is considered cylindrical. Therefore, this study aims to investigate the influences of NACA 0012 airfoil's attack angle and its positioning, that is, longitudinal and vertical placements of the cylinder relative to the airfoil, on the aerodynamic efficiency of the airfoil and entropy generation rate due to turbulent and viscous dissipations in turbulent regime. The findings indicate that the volumetric entropy generation at a angle of attack is 364.2%, 302.35%, 147.78%, and 41.51% higher than at , , , and , respectively. The aerodynamic efficiency at a horizontal distance of 60 mm is 4.76%, 5.86%, and 8.95% higher than at distances of 120, 180, and 240 mm, respectively. The maximum turbulent kinetic energy at a vertical distance of −50 mm is 9.5%, 11.36%, and 12.5% higher than at distances of −25, +50, and +25 mm, respectively.