Assessment of Turbulence Models for Aerodynamic Performance Analysis of a Commercial Horizontal Axis Wind Turbine

Abstract

In this chapter, the results of three-dimensional computational fluid dynamics (CFD) finite volume simulations of airflow around a commercial Vestas V80 Horizontal Axis Wind Turbine (HAWT), with a rated output power of 2 MW, are presented. The grid used in the simulations consists of two main parts, i.e., unstructured mesh rotating with blades and structured hexahedral stationary one for the external domain. Several cases with different free stream velocities (and different tip speed ratios and mean pitch angles) are studied, employing four different turbulence models: $k-\omega$ SST, ${\overline{\upsilon}}^2-f$, $k-\varepsilon$ RNG and Spalart–Allmaras one-equation, in order to examine their ability to predict the output generated power of HAWTs. The investigation outcomes are compared with each other and existing experimental result given in previous studies. It is shown that the numerical results are in acceptable agreement with experiments. Regarding assumptions during simulations, more sensible output power values are obtained through $k-\varepsilon$ RNG and ${\overline{\upsilon}}^2-f$ models. In addition, maximum value of power coefficient occurs at more accurate associated wind speed using ${\overline{\upsilon}}^2-f$ model. The simulations provide useful guidelines to design more efficient large commercial wind turbines.