CFD Analysis and Theoretical Modelling of Multiblade Small Savonius Wind Turbines Mihai Lates and Radu Velicu Abstract Vertical wind turbines are used in areas with non-stable wind directions or with turbulent air flows due to the reason that for a vertical wind turbine the wind direction is not an input design data—the functioning of the vertical wind turbine is not influenced by the wind direction. Built environments are characterized by turbulent air flows and small open spaces; due to that, according to the wind turbines applications, small Savonius wind turbines are used in these areas. The paper presents the finite element modeling (FEM) by using the CFD based Ansys 14.0 software of a multiblade small Savonius wind turbine and the theoretical modelling of it; the purpose of the modeling consists in finding out the wind turbines behavior depending on its blades number. Keywords Savonius wind turbine  FEM  CFD  Power coef ficient 1 Introduction Vertical wind turbines are used in areas with non-stable wind directions or with turbulent air flows due to the reason that for a vertical wind turbine the wind direction is not an input design data—the functioning of the vertical wind turbine is not influenced by the wind direction [12]. Due to the action of the wind, on the wind turbines are acting drag F D and lift F L forces; Fig. 1 presents a general sketch of the drag and lift forces. The vertical wind turbines are designed according to the type of the acting force: the functioning of Savonius type wind turbines is based on the action of the drag forces and the functioning of the Darrieus wind turbines is based on the action of the lift forces. Hybrid vertical wind turbines are using both of the forces as acting forces [6]. M. Lates (&)  R. Velicu Product Design Mechatronics and Environment Department, Transilvania University of Brasov, Brasov, Romania e-mail: latesmt@unitbv.ro © Springer International Publishing Switzerland 2014 I. Visa (ed.), Sustainable Energy in the Built Environment - Steps Towards nZEB, Springer Proceedings in Energy, DOI 10.1007/978-3-319-09707-7_30 403