Applying Proper Orthogonal Decomposition (POD) on data obtained from Large Eddy Simulations (LES) of infinitely large wind farms, stream-wise counter-rotating vortices were found to be the responsible mechanism of MKE entrainment (Verhulst and Meneveau 2014).
In the current study, the POD based analysis is extended to data from LES of finite-sized wind farms in a neutrally stratified ABL. The simulations are performed for an extremely long pressure-driven channel flow with an embedded wind farm occupying a maximum of 10% of the streamwise length. Different wind farm configurations (aligned/staggered, streamwise and spanwise spacing) are simulated to draw correlations with spatial distribution of the coherent structures.
The presence of streamwise counter-rotating rollers above wind farms hints towards a flow similarity with canopy flows where similar coherent structures are found. The analogy between wind farms and canopy flows will be explored additionally using the quadrant-hole analysis.