Wake Turbulence of Two NREL 5-MW Wind Turbines Immersed in a Neutral Atmospheric Boundary-Layer Flow

TL;DR

This study uses LES simulations to analyze wake turbulence interactions between two NREL 5-MW wind turbines in a neutral atmospheric boundary layer, revealing vortex breakdown and turbulence development downstream.

Contribution

It provides detailed fluid dynamics visualization and analysis of wake interactions between turbines using LES and actuator line modeling.

Findings

Vortices from downstream turbines break down faster due to upstream wake turbulence.

Turbulence levels increase downstream, affecting vortex stability.

Wake turbulence evolves into large-scale and smaller-scale turbulent structures.

Abstract

The fluid dynamics video considers an array of two NREL 5-MW turbines separated by seven rotor diameters in a neutral atmospheric boundary layer (ABL). The neutral atmospheric boundary-layer flow data were obtained from a precursor ABL simulation using a Large-Eddy Simulation (LES) framework within OpenFOAM. The mean wind speed at hub height is 8m/s, and the surface roughness is 0.2m. The actuator line method (ALM) is used to model the wind turbine blades by means of body forces added to the momentum equation. The fluid dynamics video shows the root and tip vortices emanating from the blades from various viewpoints. The vortices become unstable and break down into large-scale turbulent structures. As the wakes of the wind turbines advect further downstream, smaller-scale turbulence is generated. It is apparent that vortices generated by the blades of the downstream wind turbine break down faster due to increased turbulence levels generated by the wake of the upstream wind turbine.