INTERNATIONAL JOURNAL of RENEWABLE ENERGY RESEARCH M. Meziane et al., Vol.9, No.2, June, 2019 CFD Study of Unsteady Flow Through Savonius Wind Turbine Clusters Mohamed Meziane *‡ , Elhachmi Essadiqi ** , Mustapha Faqir ** , Mohamad Fathi Ghanameh ** * Condensed Matter and Renewable Energy Laboratory, Faculty of Science and Technology, Hassan II University of Casablanca, Morocco ** Université Internationale de Rabat, AERO School, LERMA Laboratoy, Rocade Rabat-Salé, 11100 Sala el Jadida, Morocco. (mezian.med@gmail.com, mustpha.faqir@uir.ac.ma, elhachmi.essadiqi@uir.ac.ma, fathi.ghannmeh@uir.ac.ma) ‡ Corresponding Author; Mohamed Meziane, Tel: +212 6 42 88 52 14, mezian.med@gmail.com Received: 04.01.2019 Accepted:29.01.2019 Abstract- The interaction between Savonius vertical axis wind turbine clusters installed in far or close proximity can devalue or enhance the output power of single Savonius vertical axis wind turbines. In this paper, the effect of spatial distribution is studied for the development of efficient Savonius vertical axis wind turbine farms. Numerical simulations are performed for a single Savonius wind turbine, sets of two rotating turbines in three different configurations (aligned, parallel and oblique configurations), and clusters of three rotating turbines, using five separation distances of 0.25D, 0.5D, 1D, 1.5D and 2D, making a total of twenty-two test scenarios. The commercial Computational Fluid Dynamics (CFD) software Fluent 15.0 is used for the numerical study. The torque and power coefficient results of single Savonius turbine are compared and validated against experimental and numerical data based on the literature review. The results showed that there was a combined effect related to the inter-turbine distance and the output power. This combined effect showed an efficient three Savonius turbine cluster having an average power coefficient 3 times higher than an isolated turbine. Best Savonius farm efficiency and high output power could be obtained by considering, at least, these two parameters. Keywords Wind energy, Vertical axis wind turbines, CFD simulation, Savonius interaction, wind farms. 1. Introduction Wind energy proves to be an alternative to fossil and nuclear energies based on efficiency [1-6]. The most efficient wind energy harvesting method consists in the use of horizontal axis wind turbines (HAWTs), that in the last years have been developing towards larger diameters (up to 160 m) and larger power production (up to 10 MW). After research studies on horizontal-axis wind turbines, which dominate the majority of the wind energy industry because of their higher efficiency, compared to vertical-axis wind turbines (VAWTs) [7-10]. Recently, vertical axis wind turbines have been receiving increasing interest. They are seen as a good candidate for installation in urban areas [11] and also as a potential candidate for the future of large-scale offshore wind turbines [12-14]. VAWTs can be classified into two categories: lift devices technology (Darrieus turbines), and drag devices technology (Savonius turbines). This type of wind turbines can operate under wind from any direction and is particularly advantageous for its lesser maintenance requirement, easier assembling, cheaper installation, and lesser aerodynamic noise [15-18]. In this present paper, a numerical simulation of the interaction between adjacent Savonius vertical axis wind turbine was conducted for renewable energy generation. This wind turbine is a simple device, designed by cutting a cylinder into halves, along its central axis and relocating the semi cylindrical surfaces sideways. The outlook of this turbine is analogous to an « S » when viewed from the top. These turbines are designed to be driven by the wind drag force and their peak power efficiency can reach up to 30% [18, 19].