- Visualizations such as these, which fuse a detailed simulation with experimental lidar data, could provide a powerful way for researchers to understand the basic physics of turbine wakes. (Courtesy of NREL. This work was supported in part by the U.S. Department of Energy, Office of Science, and Office of Workforce Development for Teachers and Scientists under the Science Undergraduate Laboratory Internship program.)
Researchers at the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL) recently installed an advanced scanning lidar on the center’s GE 1.5-megawatt test turbine as part of a project to measure and control wind turbine wakes. The work is supported by the U.S. Department of Energy, U.S. Office of Science, and U.S. Office of Workforce Development for Teachers and Scientists under the Science Undergraduate Laboratory Internship (SULI) program.
The data from the lidar will help inform researchers about the potential to steer wakes to increase efficiency of wind plant power production. While data are being collected, a group of researchers at NREL—including SULI student Shane Hicks and his mentor Kenny Gruchalla at NREL’s Computational Science Center and Senior Engineer Matt Churchfield at the NWTC—have simulated a wind turbine wake and the lidar measurement system to better understand how best to use the real lidar data when they become available. The team used NREL’s Simulator fOr Wind Farm Applications (SOWFA) to perform the simulation and created a visualization of the simulated wind turbine wake and lidar measurements using ParaView, an open-source, multiplatform data analysis and visualization application. This visualization has helped the researchers compare measurements of a model lidar to full-resolution simulation data, which is a proxy for the actual wake flow field.
The top image above represents a combination of simulated lidar data and high-resolution SOWFA simulation, revealing a clear comparison between what the lidar measures at its coarse spatial and temporal resolution and the wake in its full resolution detail.
In addition, the:
- Red line shows the current position of the simulated lidar beam
- Green and gray isosurfaces show wind flow and turbine wake speeds
- Lidar scan path shows the position of the lidar on a 7-by-7 pattern scan
- Lidar measurement visualizes the simulated lidar’s current estimate of the wake flow velocity
- Full-resolution flow sample shows the SOWFA-simulated wake velocity from which the simulated lidar takes measurements.
This visualization is helping researchers think about what the lidar can and cannot measure and how best to use it.
“Because we do not have measurement tools more comprehensive than lidar, simulation of the lidar is the best way to characterize its performance,” Churchfield said. “Given the fairly coarse resolution of remote sensing devices such as lidar compared with high-fidelity simulation, fusing a detailed simulation with experimental data could provide a powerful way for researchers to understand the basic physics of turbine wakes.”