LES Study of Wind Turbine Wake Meandering in the Atmospheric Boundary Layer

Actuator line model and CFD technique are introduced in the present work to learn the evolution of a wind turbine wake especially the wake meandering phenomenon under the atmospheric inflow condition. The simulation is implemented by applying the actuator line model to the ABL-LES solver, which is developed based on the CFD toolbox OpenFOAM by the researchers at the National Renewable Energy Laboratory (NREL). The time averaged velocity contours show that the shear layer starting behind the blade tip and root under turbulent inflow develops faster than that under uniform inflow, but under the strong mixing effect of atmospheric boundary flow the velocity inside the wake is redistributed immediately behind the rotor and the recovery process is much more accelerated than other cases. Temporal filter is used to smear out the high frequent turbulence while conserve the large scale flow structure. From the results of filtered flow field, it is found that uniform inflow and homogenous turbulent inflow cannot induce wake meandering and the large scale movement of wind turbine wake is only observed under atmospheric flow condition. Furthermore, a dominant wave length of lambda = 3.7 D and a similar meandering frequency of 0.2 < St < 0.4 in different positions downstream are obtained through further quantitative analysis.

Subjects

Large eddy simulation

Atmospheric boundary layer

Actuator line model

Wake meandering

DDC Class

600: Technik

Name

paper_0069_file_0457_LES_Study_of_Wind_Turbine_Wake_Meandering_in_the_Atmospheric_Bou.pdf

Size

1.31 MB

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Adobe PDF

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LES Study of Wind Turbine Wake Meandering in the Atmospheric Boundary Layer