ABSTRACT
A Computational Fluid Dynamic method that solves the unsteady compressible Thin-layer Navier-Stokes equations was used to simulate the unsteady flow field of the Combined Experiment Phase II rotor Horizontal Axis Wind Turbine. The methodology makes extensive use of overset grids to model the configuration. Both isolated rotor and a complete configuration that includes the rotor, hub, nacelle and tower were modeled. The isolated rotor computations show good correlation with the available experimental data. However, the low speeds had an adverse effect on solution convergence. In addition, the solutions demonstrate the importance of boundary layer transition. The solutions for rotor-tower-nacelle configuration were also compared to available field data. The predicted unsteady normal force coefficients show a tower wake interaction that has a smaller duration and amplitude in comparison to the experiment. Although these first calculations point to some regions of the flowfield where the grid needs to be improved, they demonstrate a new capability that can simulate unsteady Wind Turbine aerodynamics.
