Combined Effect of ABL Profile and Rotation in Wind Turbine Wakes: New Three-Dimensional Wake Model

Abstract

The combination of the atmospheric boundary layer (ABL) profile and the rotation of wind turbine wakes leads to lateral and vertical displacements of the wake center and to changes in the wake diameter, which are not taken into account by conventional analytical wake models. In this work, the dependence of these asymmetries on the turbulence intensity, ranging from 0.040 to 0.145, is investigated downstream using computational fluid dynamics (CFD) simulations. Based on this analysis, a new 3D Gaussian wake model is proposed. This model introduces a novel approach to define the wake diameter and center deviation based on a new length scaling. The performance of this new wake model is also optimised for a large range of downstream distances, up to 49 rotor diameters (49D). The performance of the new wake model is evaluated against other well-established models using the PyWake library as a testbench. The new model outperforms the other models over the entire turbulence range, with a few exceptions. Remarkably, the proposed model achieves satisfactory results without the need for additional ground models. In addition, the proposed model was found to have the least underestimation of the wake effect.