Evaluation of turbulence characteristics in WRF simulations at WiValdi wind park

Abstract

In this work we evaluate WRF-LES simulations at the WiValdi wind park at Krummendeich, North Germany. To accurately resolve fine-scale turbulence, we employ a high-resolution nested innermost grid with 5 m horizontal grid spacing. The main aim is to accurately reproduce realistic turbulent characteristics observed in neutral and stable atmospheric boundary layers. The so-called cell-perturbation method to accelerate the development of fine-scale three-dimensional turbulence is tested, and results are compared to in-situ observations and to another highly idealized numerical model running in LES mode. While WRF without additional modifications is capable of reproducing the mean wind fields at the WiValdi wind park, it is unable to reproduce the turbulent characteristics observed. With the cell-perturbation method included, results are significantly improved, with turbulent characteristics much closer to observations.