Numerical analysis of VAWT wind turbines: Joukowski vs classical NACA rotor's blades

As wind energy technology is growing rapidly in the energy production sector, Vertical Axis Wind Turbines (VAWTs) are coming to the fore to tackle areas with low wind speeds. The choice of optimum configuration of these VAWTs can not only maximize their performance but is a deterministic feasibility factor for their deployment. In this study, the Joukowski airfoil is reconsidered as potential rotor airfoil for VAWT. Its performance is compared against classical symmetrical NACA0012 and cambered NACA4312 blades. The investigation is carried out using high resolution CFD modelling. Results reveals the higher performance of the Joukowski airfoil over the classical symmetrical and cambered NACA. This dominance assessed by the attained higher blade lift as well as higher torque and power coefficient almost over the entire operable tip speed ratio. It was also found that cambered blades, improve the overall performance of the VAWT compared to the symmetrical baseline with a better power coefficient, at a lower tip speed ratio. In general, the rotor develops more consistent and homogenized torque at a higher tip speed ratio. The attained improvement in the torque using Joukowski however negatively affected the self-starting ability of the VAWT.