Large-scale coherent structures in the atmosphere over a flat terrain

Description

Organized or coherent motions have been widely observed within many turbulent flows, and methodologies to identify and analyze them has been developed during the last decades. Atmospheric flows are not an exception to this, and coherent structures with characteristic sizes ranging from hundreds of kilometers to centimeters are not uncommon. Large coherent motions with spatial sizes ranging up to the characteristic length scale of a wind farm are of
particular interest from a wind energy perspective, since the characterization of such structures (and their large-scale velocity fluctuations), is important to explain and model wake dynamics, which depends on the spatial variability of the mean wind speed and wind direction over the area covered by a wind farm. The development of wind lidars has opened the possibility to observe large
wind fields across many length-scales, both in space and time, which poses an unique opportunity to study organized motions over different types of terrain. Based on data from dual WindScanner long-range lidars, and the subsequent reconstruction of horizontal wind speed fields covering an area of ~ 50 km2, this work aims to identify and characterize large atmospheric coherent structures for different heights and stability conditions, as well as homogeneity and turbulence
characteristics of the flow field in general - i.e. length scale, degree of isotropy and spectra.

Period	29 Sept 2020
Held at	Delft University of Technology, Netherlands
Degree of Recognition	International