Much like the jet engines of a commercial airliner leave “jet wash” in their wake, wind turbines also disturb the air behind them as they spin, if to a lesser degree. This effect is the focus of a study called the Turbine Wake and Inflow Characterization Study (TWICS). The study is led by Julie Lundquist, assistant professor in the atmospheric and oceanic sciences department at the University of Colorado Boulder, and involves researchers from the National Oceanic and Atmospheric Administration (NOAA), the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), and the Lawrence Livermore National Laboratory (LNLL) in Livermore, Calif.
In a statement, Lundquist points out that the turbines used in today’s massive wind farm projects stretch up into a complicated part of the atmosphere. Apparently, the wakes they create at these heights could affect the atmosphere and influence other wind turbines downstream, possibly causing damage and decreasing efficiency. As part of the study, the team intends to perform experiments that will help make a detailed study of wakes created by wind turbines. The hope is that these profiles could answer questions about how gusts and rapid changes in wind direction affect turbine operations and help turbine and wind farm developers improve layout and design.
The researchers will use several methods to study the wakes and develop these profiles. One of the methods will involve using an instrument developed at NOAA called a high-resolution scanning Doppler lidar which will monitor a wind turbine at NREL’s National Wind Technology Center in south Boulder. According to LLNL, 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 has worked with the instrument and said that, while the wake effect has been studied in wind tunnels and other models, the atmosphere is very different because it is more complicated and variable.
The study will also use a specialized laser called a Windcube lidar and a sonic detection and ranging system, called a Triton sodar, to measure wind and turbulence. What’s more, NREL installed two 135 meter (about 442 ft.) tall meteorological towers to measure air temperature and provide even more wind and turbulence data.