CFD analysis of the unsteady aerodynamic behavior of a hybrid Savonius–Darrieus rotor

Hybrid Savonius-Darrieus rotors have attracted growing interest as an effective solution to enhance the performance of vertical axis wind turbines (VAWTs). By combining the high self-starting capability of the Savonius rotor with the superior aerodynamic efficiency of the Darrieus rotor, the hybrid configuration aims to improve overall power output and operational stability. In this study, an unsteady two-dimensional numerical simulation was conducted using ANSYS Fluent to investigate the transient aerodynamic behavior of a hybrid rotor. The SST k-ω turbulence model was employed to accurately capture time-dependent flow structures. The numerical model was validated against experimental data, which confirms the accuracy and reliability of the computational approach. The results reveal pronounced temporal variations in torque and pressure distribution, during rotation, highlighting the strong unsteady aerodynamic interaction between the Savonius and Darrieus components. These findings provide quantitative insight into the dynamic flow mechanisms governing hybrid rotor performance and establish a validated numerical framework for future aerodynamic optimization of VAWTs.