Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 51 6 2020 02 20 Performance Investigation of Hybrid Darrieus-Savonius Wind Turbine Compared to Straight-Bladed Darrieus Turbine by Three-Dimensional Numerical Simulation Performance Investigation of Hybrid Darrieus-Savonius Wind Turbine Compared to Straight-Bladed Darrieus Turbine by Three-Dimensional Numerical Simulation 1443 1454 2820 10.22060/mej.2018.13505.5651 FA Nozar Akbari Abolfazl Abdolahifar Aerodynamics,Aerospace Faculty,AmirKabir University of Technology(Tehran Polytechnic),Tehran,Iran Journal Article 2017 10 08 The purpose of this research is to investigate the performance of hybrid Darrieus- Savonius wind turbines to achieve a model with high starting moment and suitable performance conditions. Straight-bladed Darrieus wind turbines have high-amplitude fluctuations in moment and, at some angles, this moment is not enough to start the turbine motion. The hybrid turbine is compared with two equivalent models of straight-bladed Darrieus wind turbines. The first model has equal available power and the second model has equal height with the hybrid turbine. Three-dimensional simulation is performed using computational fluid dynamics and solving unsteady Reynolds averaged Navier-Stokes equations with finite volume method, using turbulence model and rotating mesh for rotation of the turbine. According to the results, at the self-starting, the hybrid turbine possesses 22.24% and 17.5% less standard deviation and 69.8% and 56.9% more average moment, respectively, compared to the first and second equivalent turbines. In operational mode, the hybrid turbine at the rotational speed of 30 RPM possesses 16.1% and 27.3% less standard deviation and 19.1% and 1.03% more average moment, respectively. Therefore, the hybrid turbine at the self-starting, as well as at low rotational speeds, possesses more average moment and less fluctuations compared to equivalent Darrieus turbines. The purpose of this research is to investigate the performance of hybrid Darrieus- Savonius wind turbines to achieve a model with high starting moment and suitable performance conditions. Straight-bladed Darrieus wind turbines have high-amplitude fluctuations in moment and, at some angles, this moment is not enough to start the turbine motion. The hybrid turbine is compared with two equivalent models of straight-bladed Darrieus wind turbines. The first model has equal available power and the second model has equal height with the hybrid turbine. Three-dimensional simulation is performed using computational fluid dynamics and solving unsteady Reynolds averaged Navier-Stokes equations with finite volume method, using turbulence model and rotating mesh for rotation of the turbine. According to the results, at the self-starting, the hybrid turbine possesses 22.24% and 17.5% less standard deviation and 69.8% and 56.9% more average moment, respectively, compared to the first and second equivalent turbines. In operational mode, the hybrid turbine at the rotational speed of 30 RPM possesses 16.1% and 27.3% less standard deviation and 19.1% and 1.03% more average moment, respectively. Therefore, the hybrid turbine at the self-starting, as well as at low rotational speeds, possesses more average moment and less fluctuations compared to equivalent Darrieus turbines. https://mej.aut.ac.ir/article_2820_783cb2318088a3d909eb19491849cbf9.pdf