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SWiFT site atmospheric characterization

Ennis, Brandon L.

Historical meteorological tall tower data are analyzed from the Texas Tech University 200 m tower to characterize the atmospheric trends of the Scaled Wind Farm Technologies (SWiFT) site. In this report the data are analyzed to reveal bulk atmospheric trends, temporal trends and correlations of atmospheric variables. Through this analysis for the SWiFT turbines the site International Electrotechnical Commission (IEC) classification is determined to be class III-C. Averages and distributions of atmospheric variables are shown, revealing large fluctuations and the importance of understanding the actual site trends as opposed to simply using averages. The site is significantly directional with the average wind speed from the south, and particularly so in summer and fall. Site temporal trends are analyzed from both seasonal (time of the year) to daily (hour of the day) perspectives. Atmospheric stability is seen to vary most with time of day and less with time of year. Turbulence intensity is highly correlated with stability, and typical daytime unstable conditions see double the level of turbulence intensity versus that experienced during the average stable night. Shear, veer and atmospheric stability correlations are shown, where shear and veer are both highest for stable atmospheric conditions. An analysis of the Texas Tech University tower anemometer measurements is performed which reveals the extent of the tower shadow effects and sonic tilt misalignment.

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TYPE SAND Report YEAR 2016
OSTIDOI

NRT Rotor Structural / Aeroelastic Analysis for the Preliminary Design Review

Ennis, Brandon L.; Paquette, Joshua P.

This document describes the initial structural design for the National Rotor Testbed blade as presented during the preliminary design review at Sandia National Laboratories on October 28- 29, 2015. The document summarizes the structural and aeroelastic requirements placed on the NRT rotor for satisfactory deployment at the DOE/SNL SWiFT experimental facility to produce high-quality datasets for wind turbine model validation. The method and result of the NRT blade structural optimization is also presented within this report, along with analysis of its satisfaction of the design requirements.

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TYPE SAND Report YEAR 2015
OSTIDOI

Dynamic wake meandering model comparison with varying fidelity models for wind turbine wake prediction

Annual Forum Proceedings - AHS International

Ennis, Brandon L.; Kelley, Christopher L.; Maniaci, David C.

The dynamic wake meandering model (DWM) is a common wake model used for fast prediction of wind farm power and loads. This model is compared to higher fidelity vortex method (VM) and actuator line large eddy simulation (AL-LES) model results. By looking independently at the steady wake deficit model of DWM, and performing a more rigorous comparison than averaged result comparisons alone can produce, the models and their physical processes can be compared. The DWM and VM results of wake deficit agree best in the mid-wake region due to the consistent recovery prior to wake breakdown predicted in the VM results. DWM and AL-LES results agree best in the far-wake due to the low recovery of the laminar flow field AL-LES simulation. The physical process of wake recovery in the DWM model differed from the higher fidelity models and resulted solely from wake expansion downstream, with no momentum recovery up to 10 diameters. Sensitivity to DWM model input boundary conditions and their effects are shown, with greatest sensitivity to the rotor loading and to the turbulence model.

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TYPE Conference Poster YEAR 2015
ScopusOSTI
Results 26–50 of 51
Results 26–50 of 51