Flow visualization analysis on the vertical axis Savonius water turbine by placing a cylinder in front of returning by varying stagger angle

This work will investigate the effect of the circular cylinders distance variation perpendicular the free stream installed in front of the returning to increase the turbine performance. Computational Fluid Dynamics using Gambit 2.2.30 software and ANSYS 17.0 software has been used to solve the incompressible URANS. Numerical model is validated towards experimental data at TSR 1.078. The working fluid is in verification using air at Reynolds of 4.32 x105. The ds/D is 0.5 at gap (S/D) of 0.95 with varying stagger angle of 0°, 30°, 60° and 90° with TSR of 0.3, 0.5, 0.7, 0.9, 1.1 and 1.3. The change of the stagger angle increase the turbine performance at a stagger angle of 60° followed by the increase of pressure in front side and reduce of the back of blade. In addition, stagger angle of 0° influences a circular cylinder become blockage and decrease the performance.