Two-Dimensional Spectra in the Atmospheric Boundary Layer

Abstract One-dimensional spectra are frequently used to relate features of measured and simulated meteorological field variables in the turbulent atmospheric boundary layer (ABL), but two-dimensional spectra can provide more reliable scale information than one-dimensional spectra. Here a method is presented for obtaining two-dimensional spectra from one-dimensional spectra, and it includes examples using data from large-eddy simulations and field measurements in the ABL.

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Comparison of Field Measurements and Large Eddy Simulations of the Scaled Wind Farm Technology (SWiFT) Site

Volume 4: Fluid Measurement and Instrumentation; Micro and Nano Fluid Dynamics ◽

10.1115/ajkfluids2019-5493 ◽

2019 ◽

Cited By ~ 2

Author(s):

Myra L. Blaylock ◽

Brent C. Houchens ◽

David C. Maniaci ◽

Thomas Herges ◽

Alan Hsieh ◽

...

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Wind Farm ◽

Field Measurements ◽

Operating Conditions ◽

Large Eddy Simulations ◽

Department Of Energy ◽

Large Eddy ◽

In Series ◽

The Impact

Abstract Power production of the turbines at the Department of Energy/Sandia National Laboratories Scaled Wind Farm Technology (SWiFT) facility located at the Texas Tech University’s National Wind Institute Research Center was measured experimentally and simulated for neutral atmospheric boundary layer operating conditions. Two V27 wind turbines were aligned in series with the dominant wind direction, and the upwind turbine was yawed to investigate the impact of wake steering on the downwind turbine. Two conditions were investigated, including that of the leading turbine operating alone and both turbines operating in series. The field measurements include meteorological evaluation tower (MET) data and light detection and ranging (lidar) data. Computations were performed by coupling large eddy simulations (LES) in the three-dimensional, transient code Nalu-Wind with engineering actuator line models of the turbines from OpenFAST. The simulations consist of a coarse precursor without the turbines to set up an atmospheric boundary layer inflow followed by a simulation with refinement near the turbines. Good agreement between simulations and field data are shown. These results demonstrate that Nalu-Wind holds the promise for the prediction of wind plant power and loads for a range of yaw conditions.

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Impact of Elevated Kevin-Helmholtz Billows on the Atmospheric Boundary Layer

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-21-0062.1 ◽

2021 ◽

Author(s):

Qingfang Jiang

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Shear Layer ◽

Exponential Growth ◽

Three Dimensional ◽

Large Eddy Simulations ◽

Two Dimensional ◽

Large Eddy ◽

Saturation Stage ◽

The Impact

AbstractThe impact of Kelvin-Helmholtz billows (KHBs) in an elevated shear layer (ESL) on the underlying atmospheric boundary layer (BL) is examined utilizing a group of large-eddy simulations. In these simulations, KHBs develop in the ESL and experience exponential growth, saturation, and exponential decay stages. In response, strong wavy motion occurs in the BL, inducing rotor circulations near the surface when the BL is stable. During the saturation stage, secondary instability develops in the ESL and the wavy BL almost simultaneously, followed by the breakdown of the quasi-two-dimensional KH billows and BL waves into three-dimensional turbulence. Consequently, during and after a KH event, the underlying BL becomes more turbulent with its depth increased and stratification weakened substantially, suggestive of significant lasting impact of elevated KH billows on the atmospheric BL. The eventual impact of KHBs on the BL is found to be sensitive to both the ESL and BL characteristics.

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