Abstract—Wind energy is an alternative energy driver in reducing the use of fossil energy. Investigations into Savonius wind turbines are crucial for improving turbine performance. The investigation of the performance is conducted by the overlap turbine (b) of 0.3 using experiments and numerical. The experimental study used a Savonius turbine model placed in the test section with a turbine diameter and height of 40 cm. The Savonius turbine adds a cylinder by varying g of 45°, 55°, 65°, and 75° placed on the returning position namely upstream of returning. The parameters in this study are ds/D of 0.4, and S/d of 1.7 with varying wind celerity of 5 m/s, 6 m/s, and 7 m/s. Numerical studies were carried out to validate the experimental results using the Unsteady for Realizable k-e turbulence model. The experimental study shows that the highest performance occurs at g = 55° at wind celerity of 5 m/s with the highest Cp of 0.389 and an increase in turbine performance of 18.70% compared to the original savonius wind turbine. Numerical simulations show valid values and flow phenomena indicate the performance in streamline and pressure contour. 

Keywords—Savonius, overlap, cylinder, stagger angle, returning position, power coefficient

Cite: Priyo A. Setiawan, Emie Santoso, Projek P. S. Lukitadi, Nopem Ariwiyono, Triyogi Yuwono, Anda I. Juniani, Azli A. Razak, A.Grummy Wailanduw, Hafiyyan A. Wicaksono, and Naffatsa A. Wiyoga, "Investigation on Improving Performance by Varying Stagger Angle of Cylinder in Returning Position to Overlap Savonius Wind Turbine," International Journal of Mechanical Engineering and Robotics Research, Vol. 15, No. 4, pp. 413-422, 2026. doi: 10.18178/ijmerr.15.4.413-422

Copyright © 2026 by the authors. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).