Effects of the fidelity level of numerical simulations on the wake meandering phenomenon

The aim of this paper is to verify that a modeling approach affordable at wind farm scale, inthis case a fourth-order finite differences code combined with a rotating actuator disk, providesequivalent results in terms of wake meandering compared to a method with a higher fidelitylevel, i.e. a Vortex Particle-Mesh Method combined with immersed lifting lines. The analysisis performed on the wake centerlines obtained from Large Eddy Simulations of an isolatedNREL 5-MW wind turbine subject to several synthetic turbulent inflows: 6%, 10%, and 15%turbulence intensity. A direct comparison of the wake centerlines reveals a good match betweenthe two approaches up to five rotor diameters. Concerning the amplitude and wavelength of thewake meandering, the lower fidelity code leads to larger amplitudes and shorter wavelengths.Assuming that Taylor’s frozen turbulence hypothesis is applicable, the Strouhal numberStiscomputed as the ratio between the rotor diameter and the wavelength. Obtained values aresuch that 0.2 < St <0.4.