Aerodynamical phenomena in a large top covered wind mill with vertical axis wind turbine

Purpose – The purpose of this paper is to examine the aerodynamical and air mass flow phenomena taking place in the channel of a modified version of one of the well-known Sistan wind mills, in order to improve its aerodynamic performance. Design/methodology/approach – The simulations are done by means of the finite volume method associated to the realizable k-ε turbulence model. The computational domain consists in a rotating sub domain including the wind turbine equipped with nine blades and a fixed sub domain including the rest of the computational domain. Both are connected by means of a sliding mesh interface. Calculations are done for 8×105-4×106 Reynolds number range, corresponding to inlet velocities varying from 2 to 10 m s−1. Findings – The velocity fields are presented for the stopped and operating turbine (static and dynamic conditions). A careful examination of the aerodynamic phenomena is performed to detect potential vortices that could develop in the central cavity of the active assembly, and then influence the wind turbine’s operation. Originality/value – The modification proposed in this survey is easy to realize, consisting in covering the top of the entire original assembly that avoids the extraction of a large part of the air mass flow occurring through the open top of the original version. The aerodynamic phenomena occurring across the channel of this large vertical axis wind turbine are substantially different from those of the original version.