Comparison of 2D and 3D Simulations on Predicting the Performance of a Savonius Wind Turbine

Abstract

The performance of Savonius rotors plays a vital role in harnessing wind energy for various applications. This study aims to investigate and compare the performance characteristics of Savonius rotors using two-dimensional (2D) and three-dimensional (3D) analysis approaches. The primary objective is to determine the optimal analysis method for evaluating the rotor's performance. The simulations were conducted using ANSYS software, considering six different tip-speed ratios (TSRs) ranging from 0.2 to 1.2, and three wind speed categories (7 m/s, 5 m/s, and 3 m/s). The hybrid shear-stress transport (SST) k-omega was used as the turbulence model. The results indicate that the 2D analysis approach, which simplifies the rotor's geometry by assuming rotational symmetry, provides reasonable estimations of the rotor's performance. However, the 3D analysis captures the intricacies of the rotor's actual geometry, accounting for the effects of non-uniform flow and vortex shedding, which can significantly influence the rotor's performance. The comparative analysis reveals that the 3D analysis predicts higher torque and power coefficients than the 2D approach, especially at higher wind speeds. At TSR 1.0, the torque and power coefficient obtained from the 3D approach are 6.56 Nm and 0.102, respectively meanwhile 2D approach gains 6.28 Nm torque and 0.098 for power coefficient. This research contributes to a better understanding of the performance characteristics of Savonius rotors and highlights the importance of considering three-dimensional effects in their analysis. The findings can guide the design and optimization of Savonius rotor systems, leading to improved wind energy conversion efficiency and enhanced utilization of renewable energy resources.