R&D News: Wind turbines produce wakes of invisible ripples
The issue was being researched in a newly launched study led by CU-Boulderâ€™s Julie Lundquist, assistant professor in the atmospheric and oceanic sciences department.
The study, called the Turbine Wake and Inflow Characterization Study, or TWICS, also includes researchers from the National Oceanic and Atmospheric Administration, the US Department of Energy's National Renewable Energy Laboratory, or NREL, and the Lawrence Livermore National Laboratory in Livermore, California.
Scientists and wind energy developers will use results of the study to better understand power production and increase the productivity of wind farms, according to the researchers.
Lundquist, who also is a joint appointee at NREL, said: â€œToday's massive wind turbines stretch into a complicated part of the atmosphere. If we can understand how gusts and rapid changes in wind direction affect turbine operations and how turbine wakes behave, we can improve design standards, increase efficiency and reduce the cost of energy.â€
To measure wind shifts and wake behavior, the researchers will monitor a wind turbine at NREL's National Wind Technology Center in south Boulder, using an instrument developed at NOAA called a high-resolution scanning Doppler lidar. The lidar produces three-dimensional portraits of atmospheric activity and can capture a wedge of air up to 3,280 feet from the ground and 4.3 miles long.
Robert Banta, an atmospheric scientist with NOAA's Earth System Research Laboratory and a TWICS researcher, has worked with the instrument for several years.
â€œThe wake effect has been modeled in wind tunnel studies and numerical models,â€ said Banta, â€œbut the atmosphere is different, it's more variable and complicated.â€
Researchers also will use a specialized laser called a Windcube lidar and a sonic detection and ranging system, called a Triton sodar, to measure wind and turbulence. In addition, NREL has installed two meteorological towers, each 135 meters tall, which will be used to measure air temperature, as well as wind and turbulence.
Lundquist said: â€œEven fluctuations in air temperature throughout the day can affect wind turbine wakes. The resulting changes in wake behavior can impact the productivity of wind farms with many rows of turbines, so it's important to observe them in detail and understand how to minimize their impacts.â€
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