Numerical Investigation on a Series of Parabolic Profiles to Arrive at an Optimum Design Based on the Savonius Wind Rotor

Savonius vertical-axis wind turbines are simple, cost-effective, and can create off-grid electricity. The blade’s profile shape is one of the main parameters determining the turbine’s performance. The novelty of the work presented here is that it investigates the performance of the various parabolic profiles on the turbine to arrive at an optimum design. The position of the parabola’s vertex is varied to produce forty-eight parabolic profiles, but each design’s overall diameter remains constant. The shear stress transport k- ω turbulence model is used to solve two-dimensional unsteady Reynolds-averaged Navier–Stokes equations at a Reynolds number of 0.891 × 10⁵. The result shows that the maximum power coefficient (C_Pmax) and maximum drag coefficient (C_Dmax) of the optimum parabolic profile enhanced the rotor performance by 10.34% and 16.41% compared to the conventional semicircular profile. The effects of the Reynolds number are also studied in the present investigation, and the results show that with an optimum Reynolds number of 1.01 × 10⁵, the optimum parabolic profile improved the C_Pmax by 14.24%. The velocity, total pressure and turbulence intensity contours are also presented to give a better insight into its distribution due to the changes in the profile shape of the blade.