Natural snowfall reveals large-scale flow structures in the wake of a 2.5-MW wind turbine

Jiarong Hong, Mostafa Toloui, Leonardo P. Chamorro, Michele Guala, Kevin Howard, Sean Riley, James Tucker, Fotis Sotiropoulos

Research output: Contribution to journalArticlepeer-review

105 Scopus citations


To improve power production and structural reliability of wind turbines, there is a pressing need to understand how turbines interact with the atmospheric boundary layer. However, experimental techniques capable of quantifying or even qualitatively visualizing the large-scale turbulent flow structures around full-scale turbines do not exist today. Here we use snowflakes from a winter snowstorm as flow tracers to obtain velocity fields downwind of a 2.5-MW wind turbine in a sampling area of ∼n36 × 36 m 2. The spatial and temporal resolutions of the measurements are sufficiently high to quantify the evolution of blade-generated coherent motions, such as the tip and trailing sheet vortices, identify their instability mechanisms and correlate them with turbine operation, control and performance. Our experiment provides an unprecedented in situ characterization of flow structures around utility-scale turbines, and yields significant insights into the Reynolds number similarity issues presented in wind energy applications.

Original languageEnglish (US)
Article number4216
JournalNature communications
StatePublished - Jun 24 2014

Bibliographical note

Funding Information:
This work was supported by a grant from the US Department of Energy (DE-EE0002980), which established the Eolos wind energy field station, and the resources provided by the University of Minnesota College Of Science and Engineering, Department of Mechanical Engineering and St Anthony Falls Laboratory as part of the start-up package of J.H. We also thank the engineers from St Anthony Falls Laboratory, especially James Mullin, Chris Ellis, Jeff Marr, Chris Milliren and Dick Christopher, for their assistance in the experiments, and Professor Joseph Katz from Johns Hopkins University for his suggestions in improving our manuscript.


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