Wind energy is a clean, renewable, and endless energy source that can lower greenhouse gas emissions, it has grown to be an important component of the global sustainable energy mix. The current study assesses the impact of creating tubercles on a wind turbine air foil’s leading edge in terms of flow across the airfoil as well as lift and drag performance. Tests and comparisons with the base airfoil are conducted with different tubercle configurations. In both the pre-stall and post-stall regimes, the wind velocity is assumed to be 10 m/s, 15 m/s, 20 m/s, and 25 m/s for a variety of angle of attack values. The turbine blade performance in this work is measured using the standard NACA0012 profile. The κ–ω turbulence model has been used for the numerical simulation. Based on the numerical investigations, it has been found that the tubercles-induced airfoil shows a delayed flow separation which in turn enhances the aerodynamic performance under the post-stall regime (at a higher angle of attack).