Wake predictions of full HAWT rotor and actuator disk model CFD simulations using different RANS turbulence models compared to experimental measurements

The development of large scale wind energy projects created the demand for increasingly accurate and efficient models that limit the project’s uncertainties and risk. Wake effects are of great importance and together with the complex terrain effects are employed to the optimization process of wind farms. Despite the growing body research there are still many open questions and challenges to overcome. To investigate the physics involved in a single wake, full wind turbine rotor simulations are compared with a simplified actuator disk model that is used by the industry for wind farm applications. The steady state 3-D Reynolds-Averaged Navier Stokes (RANS) equations are solved in the open- source package OpenFOAM, using different two equation turbulence models. For the full-rotor computational fluid dynamics (CFD) simulations, the multiple reference frame (MRF) approach was used to model the rotation of the blades and hub geometries. For the simplified cases, the actuator disk model was used with the experimentally measured thrust (Ct) and pressure (Cp) coefficient values. The performance of each modelling approach is compared against wind tunnel wake measurements of the 4th blind test organized by NOWITECH and NORCOWE in 2015.