Wind turbine wake visualization and characteristics analysis by Doppler lidar

Area of Science:

• Renewable Energy Engineering
• Atmospheric Science
• Fluid Dynamics

Background:

• Wind power is a key renewable energy source, but wind turbine wakes reduce efficiency and increase fatigue loads.
• Understanding and mitigating wake effects are critical for optimizing wind energy production.

Purpose of the Study:

• To develop and deploy a pulsed coherent Doppler lidar (PCDL) for visualizing and characterizing wind turbine wakes.
• To assess the PCDL's capability in observing instantaneous turbulent wind fields and its effectiveness compared to existing technologies.

Main Methods:

• Developed a PCDL with a 4 Hz update rate and variable spatial resolution (15-60 m).
• Employed single and dual Doppler lidar techniques to analyze wake features like velocity deficit, dimensions, and turbulence intensity.
• Validated wind speed estimation using arc scan techniques against wind mast measurements.

Main Results:

• The PCDL successfully visualized wind turbine wakes and characterized their geometry and dynamics.
• Detailed analysis of wake features, including wind velocity deficit, wake dimensions, and turbulence characteristics, was performed.
• Field experiments in onshore and offshore wind farms provided insights into turbulent wind fields.

Conclusions:

• The developed PCDL is a practical and effective tool for wind energy research.
• Findings provide a significant basis for wind farm site selection, design, and optimization.
• Improved understanding of wake dynamics can lead to more efficient and durable wind turbine operations.