Numerical investigation of a savonius wind turbine with different blade overlap distances

This study examines the aerodynamic efficiency of a Savonius-type vertical-axis wind turbine with various blade gap configurations at different wind speeds through numerical methods. Blade gaps of 10 mm and 20 mm were examined at constant inlet wind velocities of 3, 7, and 11 m/s using two-dimensional transient Computational Fluid Dynamics (CFD) models. The numerical studies utilised the standard k–ε turbulence model to minimise computational expenses, employing a time step of 0.002 seconds across a total simulation period of 15 seconds. The findings indicate that the 10 mm blade gap consistently surpasses the 20 mm arrangement across all wind speed conditions. The findings demonstrate that a diminished blade gap markedly enhances flow organisation, torque stability, and energy conversion efficiency, underscoring the promise of optimised Savonius rotor geometries for small-scale and low-wind renewable energy applications.