the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 28 Sep 2023
The fractal turbulent/non-turbulent interface in the atmosphere
Matthias Wächter
Joachim Peinke
Abstract. With their steady growth in size, wind turbines are reaching unprecedented heights. As a result, at these heights they are affected by wind conditions that have not yet been investigated in detail. With increasing heights, a transition to laminar conditions becomes more likely. In this paper, the presence of the turbulent/non-turbulent interface (TNTI) in the atmosphere is studied. Three different sites are investigated. Our fractal scaling analysis leads to typical values known from ideal laboratory and numerical investigations. The height distribution of the probability of the TNTI is determined and shows a frequent occurrence at the height of the rotor of future multi megawatt turbines. The indicated universality of the fractality of the TNTI allows the use of simplified models in laboratory and numerical investigations.
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Lars Neuhaus et al.
Status: final response (author comments only)
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RC1: 'Comment on wes-2023-73', Anonymous Referee #1, 13 Oct 2023
The comment was uploaded in the form of a supplement: https://wes.copernicus.org/preprints/wes-2023-73/wes-2023-73-RC1-supplement.pdf
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RC2: 'Comment on wes-2023-73', Anonymous Referee #2, 09 Nov 2023
This paper presents a study to investigate the Turbulent/Non-turbulent interface in the atmosphere using measurements from met masts and lidars on two offshore and one onshore windsite. Existence of the TNTI interface and its probability distribution with height as well as its fractal scaling is studied. The paper is well written in general. Use of English language needs improvement as to some expressions and descriptions sound strange. Some comments are below:
In Section 4.1, authors mention that strong influence of measurements techniques are expected but they indicate that this is out of scope for this study. I understand that but I think the authors should elaborate somewhat more since these differences may influence the results presented in this paper. The anemometers sample at 1 Hz and 2 Hz sampling rates but the Lidars provide temporal data with a resolution at every 17 or 18 s. So there is a big difference in sampling rates. Please provide some comments regarding the effects of these big differences on presented results.
In Figure 8c, the data shows very wide pdf distributions at low heights unlike other Cabauw data. Authors allude that this could be due to differences in measurement methods. Please elaborate. Why are there significant characteristic differences in pdf distributions between the metmast data and the Lidar data at Cabauw?
In Figure 8a the color scale is poorly chosen. It's hard to distinguish 100 m and 33 m data for example.
Citation: https://doi.org/10.5194/wes-2023-73-RC2
Lars Neuhaus et al.
Lars Neuhaus et al.
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