Impact of Aerofoil Shapes on the Performance of Darrieus Vertical Axis Turbines: A Computational Study for Offshore Wind and Hydro Applications

Abstract An increasing energy demand, coupled with the depletion of fossil fuels and rising pollution levels, necessitates a shift towards renewable energy sources. Wind and hydro energy are a prominent renewable energy source, constituting more than 20% of the global electricity production. The objective of this study is to investigate the influence of different aerofoil shapes on the performance of Darrieus vertical axis turbine for the optimum tip speed ratio of 3.0 using Computational Fluid Dynamics (CFD) simulations. The focus is on six aerofoil profiles, namely, NACA 0012, NACA 0021, NACA 0030, S-1046, NACA 4421 and NACA 2412. Open-source CFD software OpenFOAM 9.0 is employed to perform two-dimensional unsteady Reynolds-Averaged Navier-Stokes (U-RANS) simulations using the SST k-ω turbulence model. This approach allows for the analysis of fluid characteristics around the turbine blades and an assessment of the aerodynamic performance of Darrieus turbine. The observed results provide an insight into the performance of various aerofoil profiles and help understand their strengths and shortcomings. By comparing the results, the aerofoil shape that yields the highest performance under the given conditions is identified. Additionally, the study investigates the effect of using asymmetric aerofoils on Darrieus turbine performance. This study is relevant to the optimization of the aerofoil shapes which can further enhance the efficiency and effectiveness of Darrieus turbines.