<![CDATA[Savonius vertical axis wind turbines (SVAWTs) are attractive for urban and distributed energy applications because of their simple construction, omnidirectional wind acceptance, and self-starting capability, but their performance is limited by relatively low aerodynamic efficiency and high cut-in wind speeds. This study experimentally investigates a modified SVAWT that combines NACA0024 aerofoil sections at the blade extremities with an adjustable half-cylinder aerodynamic augmentation shell. The integrated configuration is evaluated as a proof-of-concept under controlled wind-tunnel conditions using both no-load and electrical-load measurements. The turbine was positioned at the exit of an open wind tunnel and tested over tunnel speeds of 9–18 m/s. The shell-assisted configuration reduced the cut-in tunnel speed from 12 to 9 m/s, increased rotational speed by up to 30%, and improved no-load voltage output by approximately 10–27%. Under resistive loading, the maximum power coefficient increased from 0.0086 to 0.0172 at 15 m/s, while peak electrical power increased by approximately 140% at 12 m/s, 100% at 15 m/s, and 68% at 18 m/s. The shell-assisted configuration also reduced the outlet-to-inlet velocity ratio and broadened the operating range over which higher torque coefficients were maintained. However, the tip-speed ratio remained below unity under all test conditions, and the absolute power coefficients were low because of the small prototype scale, low Reynolds number, absence of endplates, and rotor-generator constraints. The results demonstrate that the combined aerofoil-tip and shell configuration can provide measurable relative performance improvements compared with the same rotor operated without the shell. Further work is required to optimize the shell and aerofoil parameters, validate the flow mechanism directly, and assess performance at higher Reynolds numbers and under realistic urban wind conditions. ]]>
