Title:
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Turbulence assessment with ground based lidars
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Author(s):
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Published by:
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Publication date:
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ECN
Wind Energy
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23-9-2014
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ECN report number:
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Document type:
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ECN-E--14-043
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ECN publication
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Number of pages:
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Full text:
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26
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Download PDF
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Abstract:
One of the tasks of the LAWINE project concerns the analysis and development of measurement technology and data processing technology to apply ground based LiDARs to wind resource assessments and turbulence assessments. Since turbulence intensity measurement with the ground based LiDAR principle requires special attention, the current study focusses on turbulence assessment with two ground based LiDARs vs a meteorological mast at the ECN Wind turbine Test site Wieringermeer (EWTW).
In general, the results with the LiDARs are in better agreement with the sonic anemometers than with the cups. Especially at lower wind speeds (< 4 m/s), the turbulence intensities measured with cups result in approximately 2-4% lower values compared to sonic anemometers, and 2-6% lower values compared to LiDARs. At higher wind speeds (>5 m/s), the LiDARs measure slightly lower turbulence intensities (<0.5%) compared to sonic anemometers, and higher turbulence intensities (<1%) compared to cups.
In general, turbulence intensities measured with the ground based LiDARs are in between the results measured with cups and sonics, which demonstrates that the accuracy of the LiDAR technique for turbulence measurements is satisfactory. Moreover, the reproducibility of the LiDAR technique turned out to be very good.
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