Hierarchical Methodology for the Numerical Simulation of the Flow Field around and in the Wake of Horizontal Axis Wind Turbines: Rotating Reference Frame, Blade Element Method and Actuator Disk Model

Abstract

A hierarchy of computational methods for Horizontal Axis Wind Turbine (HAWT) flow field is proposed, focusing on rotor models for Reynolds-Averaged Navier-Stokes simulations. Three models are systematically compared to determine their adequacy to capture performance and wake dynamics, and the trade-offs between accuracy and computational cost. The Rotating Reference Frame model is prescribed for detailed flow field studies, specifically at the root and blade tip. The Blade Element Model does not reproduce the near wake region but successfully predicts the velocity deficit in the axisymmetric far wake, and the power and torque coefficients. The Actuator Disk Model underestimates the velocity deficit in the far wake, but can be corrected to perform simulations of large wind farms. This methodology is applied to a canonical rotor and compared against experimental data. These models span three orders of magnitude in computational time and cost for the study of HAWT aerodynamic performance and wake interaction.