Analysis of wake properties and meandering under different cases of atmospheric stability: a large eddy simulation study

Abstract

Abstract Large eddy simulations (LES) with the solver Meso-NH are performed to analyse a single wind turbine wake. In the first part of this work, four algorithms to determine the instantaneous wake centre (wake tracking) from the literature are compared. A data-processing method is also proposed to improve the results of these algorithms. In the second part, three different atmospheric conditions are simulated to assess the effect of inflow conditions on the wake. The focus is on the 2-dimensional wake width, the maximum deficit, the maximum added turbulence and the amount of wake meandering in the lateral and vertical directions. The three formers are computed in both the Moving and Fixed Frames of Reference (MFOR and FFOR). Results in the MFOR are shown to be sensitive to the wake tracking algorithm, in particular for turbulence. The flowfield in the MFOR is found to be independent of atmospheric conditions for the two cases with similar operating conditions and length scales larger than two diameters of the rotor. The third case with lower length scales and turbulence intensity behaves differently.