Abstract
A comparison is made between the EllipSys3D and SnS CFD codes. Both codes are used to perform Large-Eddy Simulations (LES) of single wind turbine wakes, using the actuator disk method. The comparison shows that both LES models predict similar velocity deficits and stream-wise Reynolds-stresses for four test cases. A grid resolution study, performed in EllipSys3D and SnS, shows that a minimal uniform cell spacing of 1/30 of the rotor diameter is necessary to resolve the wind turbine wake. In addition, the LES-predicted velocity deficits are also compared with Reynolds-Averaged Navier Stokes simulations using EllipSys3D for a test case that is based on field measurements. In these simulations, two eddy viscosity turbulence models are employed: the k-ϵ model and the k-ϵ-fp model. Where the k-ϵ model fails to predict the velocity deficit, the results of the k-ϵ-fP model show good agreement with both LES models and measurements.
Highlights
Over the last few decades, wind turbine wakes have become an important research topic in wind energy, because wake turbulence can increase loading on wind turbines and cause power loses in wind farms [1]
The Large-Eddy Simulations (LES)-predicted velocity deficits are compared with Reynolds-Averaged Navier Stokes simulations using EllipSys3D for a test case that is based on field measurements
Since a turbulence model is redundant, the test case is ideal to investigate the forcing of the Actuator Disk (AD) applied in EllipSys3D and SnS
Summary
Over the last few decades, wind turbine wakes have become an important research topic in wind energy, because wake turbulence can increase loading on wind turbines and cause power loses in wind farms [1]. Simulating wind turbine wakes in Computational Fluid Dynamics (CFD) is one way of providing a better understanding of the flow around a wind turbine and the wake interaction in a wind farm. Large-Eddy Simulation (LES) is one possible CFD method, but it is relatively expensive to solve for a wind turbine wake [2]. The widespread k-ε Eddy-Viscosity Model (EVM) is known for under-predicting the velocity wake deficit, which is related to the fact that the eddy-viscosity coefficient Cμ is a constant in the k-ε EVM. In regions with high shear, e.g. the edge of a wind turbine wake, Cμ is much lower compared to the original k-ε EVM. The eddyviscosity in the wind turbine wake decreases and the recovery of the velocity deficit is delayed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
