Table 1: Summary of experimental investigation carried out by researchers on Savonius turbines with water as working medium.

AuthorTurbine aspect ratio (H/D)Reynolds number ×105Free stream velocity (m/s)Water tunnel dimensions ( )Orientation of the axisTurbines testedParameters measuredResults

Khan et al. [8]1.820.98, 1.52, 1.961 5 × 3VerticalSingle-stage, two- stage, three-stage conventional Savonius turbines with an overlap ratio of 0.207 , of 0.038, 0.049 and 0.04 for single-, two- and three-stage Savonius turbines

Nakajima et al. [9]1.481.10.80.6 × 0.5HorizontalSingle-stage conventional Savonius turbine , flow visualisation of 0.25 for single-stage Savonius turbine

Nakajima et al. [10]1.2, × 0.5HorizontalSingle-stage and two-stage conventional Savonius turbine with an overlap ratio of 0.36 , flow visualisation of 0.275 for two stage with 90° phase shift compared to 0.25 for single-stage turbine and flow visualisation gives the torque generation mechanism

Faizal et al. [11]4.54No details available0.20.45 × 0.3VerticalSingle-stage conventional Savonius five-bladed turbine , Rotational speed of the turbine increases with increase in the wave height and wave frequency