Report · Printed book
Tændpibe wind farm measurements 1988
Data from a field program on a wind farm in Denmark is reported. High frequency measurements of windspeeds and directions at several heights were measured inside the windfarm as well as upstream of the farm. Also mean power output and power fluctuation levels were measured. The results have been compared with the simple Risø PARK model for average power output of a windfarm.
The model was shown to be capable of accurately modelling the wind farm output. The turbulence inside the farm was investigated in detail. The average levels of turbulence in such a farm seem to reach an equilibrium level of 20-25% at the highest point of the measurements, 30 m (somewhat above hubheight) and still increasing with height.
This level of turbulence could be generated by a freestream roughness length of the order of 0.5 m. The spectral decomposition of the turbulent velocity fluctuations showed that the main amount of excess energy inside the farm compared with upstream, was found at a shallow maximum around 0.1 Hz (or in terms of wavelength around 60 m).
The turbulence inside the windfarm could not be described by ordinary homogenous terrain parameterizations, except for the vertical fluctuations that apparently attained a local equilibrium. The horizintal components were far from their equilibrium values. (author).
Language: | English |
---|---|
Year: | 1990 |
Volume: | 2894 |
Pages: | 44 s. |
Series: | Risø-m |
ISBN: | 8755016758 and 9788755016750 |
ISSN: | 04186435 |
Types: | Report and Printed book |