Modelling the Wake Flow Behind a Model of Horizontal Axis Wind Turbine using RANS Approach: A Comparative Study

Abstract

Steady CFD simulations, which is based on Reynolds Average Navier-Stokes (RANS) approach, were conducted for a model of Horizontal Axis Wind Turbine (HAWT) and compared with experimental data in order to assess the accuracy of these models in simulating the wake flow of HAWTs. The models can be categorized into two categories: fully developed models (Standard k-ε model, Realizable k-ε model, and SST k-ω model) and transitional models (K-kl-ω transition model and Transition SST Model). In this paper, ANSYS FLUENT 19.2 was being used to execute the simulations of the model turbine standing on a closed-loop wind tunnel at Norwegian University of Sciences and Technology (NTNU). Experiments were operating on a high turbulence intensity uniform inflow. Velocity, turbulence intensity, and turbulent kinetic energy profiles are illustrated at two downstream cross sections. Furthermore, contours of these parameters are set to investigate the developing of wake flow behind the turbine. It is demonstrated that models reasonably predict the velocity profile at the wake region. Transitional models are more accurate in predicting the power of the turbine. Turbulent kinetic energy and turbulence intensity were underestimated for all models.

Keywords

• cfd
• turbulence modelling
• rans
• wake effect
• hawt