@article{oai:soar-ir.repo.nii.ac.jp:00012575,
 author = {Nakajima,  M and Iio,  S and Ikeda,  T},
 issue = {3},
 journal = {Journal of Fluid Science and Technology},
 month = {},
 note = {The aim of this investigation is to develop an environmentally friendly nano-hydraulic turbine. Three type models of Savonius rotor are constructed and tested in a water tunnel to improve and clarify the power performance. Flow field around the rotor is examined visually to reveal the enhancement mechanisms of power coefficient using the double-step rotor. Flow visualization showed the difference of flow patterns at the central section between the standard (single-step) rotor and the double-step one. A meandering flow in the axial direction of the rotor was observed only for the double-step rotor. This flow had the pressure restoration effect at the returning blade's concave side and the torque strengthened effect at the advancing blade's convex side. As a consequence, the power coefficient was 10% improved., Article, Journal of Fluid Science and Technology. 3(3):410-419 (2008)},
 pages = {410--419},
 title = {Performance of Double-step Savonius Rotor for Environmentally Friendly Hydraulic Turbine},
 volume = {3},
 year = {2008}
}