Mohammed  made a comparison between two and three blades Savonius wind turbine
. Two models of two and three blades were designed and fabricated from Aluminum sheet, each of them had an aspect ratio of (H/D =1), the dimension was (H = 200 mm height and diameter D = 200 mm) and the blades were made of semi - cylindrical half of diameter (d = 100 mm).
 Abdullah Al-Faruk, Ahmad Sharifian, "Geometrical optimization of a swirling Savonius wind turbine
using an open jet wind tunnel", Alexandria Engineering Journal, Available online 30 July 2016, http://dx.doi.org/10.1016/j.aej.2016.07.005
Preliminary development of prototype of Savonius wind turbine
for application in low wind speed in Kuala Terengganu, Malaysia.
Abdallah, "Numerical study of two-bucket Savonius wind turbine cluster," Journal of Wind Engineering and Industrial Aerodynamics, vol.
Sobczak, "Numerical investigation of conventional and modified Savonius wind turbines," Renewable Energy, vol.
This design principle can be used in future to increase the efficiency of Savonius wind turbine
In the 1970s, plans for vertical-axis and Savonius wind turbines