Application of the Reynolds Stress Model to Direct Modeling and Actuator Disk Simulations of a Small-Scale Horizontal-Axis Wind Turbine

Computational Fluid Dynamics (CFD) has become a staple in wind energy research and studies cover a broad range of topics including atmospheric wind profiles, airfoil design, wind turbine design, terrain effects, and wake dynamics. One of the most important aspects of applying CFD methods is the selection of a turbulence closure model when solving the Reynolds Averaged Navier-Stokes (RANS) equations. In this research, the Reynolds Stress Model (RSM) was applied to predict the wake turbulence and velocity profiles for a small scale, 3-bladed, horizontal-axis wind turbine (HAWT) using a commercial CFD software, Star CCM+. The wind turbine was modeled directly by discretizing the rotor and also using an actuator disc concept to simulate the rotor. Wind tunnel experiments were performed using hot-wire anemometry to measure the velocity deficit at various downstream locations. High speed images were also captured to examine qualitatively the wake and tip vortex dissipation created from an oil mist. The CFD results show the RSM turbulence closure model to be excellent in predicting the wake velocity and tip vortex structure when compared to experimental results.