Evaluation of influence of turbulence models on the vortex formation processes modeling in wind power

The paper studies the results of mathematical modeling of the external flow of Siemens 3D model SWT–3.6–120 (B52 air foil) horizontal axis wind turbine (HAWT), using the Navier–Stokes equations averaged by Reynolds (RANS) closed by $k{-}\varepsilon$, $k{-}\omega$ Shear Stress Transport (SST) and Eddy Viscosity Transport (EVT) turbulence models. The task of correct determination of the wind speed vector deviation angle over the nacelle of the HAWT is required by operation of the yawing system, which determines in turn the efficiency of the entire turbine. The Struhal number was chosen as a comparison criterion, defined for the transverse flow around the cylinder, describing the frequency of the formation of vortex structure behind the butt part of the blade of the HAWT. The calculated area consists of 3 million tetrahedral volumes with prismatic layer on the surface of the nacelle, using local grinding. The place of flow direction parameters registration is located at a height of 3 m above the nacelle and at a distance of 8 m from the blade shank, which corresponds to the standard location of the weather vane. The analysis of the obtained results showed that the $k{-}\varepsilon$ and EVT turbulence models describe the flow parameters over the HAWT nacelle in almost the same way, but the EVT model represents just one differential equation, thereby it is preferable by the computational cost criterion. Also, one of the advantages of one-parameter turbulence model (EVT model) is a smaller number of closing semi-empirical constants, the analysis of which allows the expanding of the engineering techniques scope for the modeling of turbulent processes in solving the practical problems related to the design of control systems for the wind turbines, increasing their efficiency.