Effect of Vortex Generations on Aerodynamic Performance of Rough Wind Turbine Airfoil

Abstract

Experimental investigations were carried out in wind tunnel facilities to assess the effect of vortex generators on the aerodynamic characteristics of a NACA4418 airfoil, particularly in scenarios where surface roughness is precipitated by environmental elements like dust, sand, and insects. These elements are known to adversely affect the efficiency of power generation. These studies meticulously analyzed the airfoil’s pressure distribution and its aerodynamic coefficients, taking into account the roughness positioned at varying locations along the chord. Special attention was given to the roughness located at 0.2c due to its pronounced impact on aerodynamic efficiency. The research highlighted that vortex generators play a crucial role in mitigating boundary layer separation, thereby enhancing the lift-to-drag ratio, especially at higher angles of attack. Notably, the deployment of vortex generators on airfoils affected by surface roughness resulted in a more pronounced improvement, elevating the maximum lift coefficient by 11.6% compared to their effect on smooth airfoils. Furthermore, the study revealed that an increase in the Reynolds number significantly augments the benefits provided by vortex generators, improving the lift coefficient and delaying the stall angle for airfoils with surface roughness, while also shifting the boundary layer separation point towards the airfoil’s trailing edge.