Numerical Study of Savonius Wind Turbines with Standard and Bach-Profile Blade Variations

Numerical analysis is performed on Savonius turbine rotor with the standard blades and Bach-profile blades. The standard configuration was taken as a half semi-circular cylinder with overlap. Savonius turbine with overlap blades is considered because it gives better performance compared to that without overlap. Meanwhile, the Bach-profile blades tested are varied with arc surface angles of 1240 degrees and 1350 degrees The objective of the study is to compare the performance of the Savonius turbine with standard blades with overlap to that with Bach-profile blades, particularly at very low wind speed. Steady, two-dimensional numerical simulations were performed on Savonius rotor turbine. Reynolds-Averaged Navier Stokes solver was used to solve the computations, with the turbulence model of the transition k-kl-omega model. The simulations were run at constant freestream velocities of 4 m/s and 7 m/s, and at various rotor angle positions. Overall, the results show that the rotor with the Bach-profile blade with arc surface angle of 135 degrees has the highest static torque coefficient compared to other profile blades, for both the velocities tested. The self-starting capabilities are approximately similar for all the blade type tested.