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Notes - Wind Turbine ISR-G (view source)
Revision as of 14:50, 24 September 2020
, 14:50, 24 September 2020no edit summary
- averaging periods of 10 min are commonly used; 30 min period for turbulence studies; the larger integral time scale, the larger should be averaging period; sampling frequencies should be much smaller than integral time scale
- you have to detrend te time series to get rid of high-frequency fluctuation
_Sources_:
[Turbulence Spectra and Scales](http://brennen.caltech.edu/FLUIDBOOK/basicfluiddynamics/turbulence/turbulencescales.pdf)<br>
<blockquote>Transition to turbulence begins when some flow instability
(such as the instability analyzed in sections (Bkc) and (Bkd)) leads to some fairly large scale disturbance(s)
or “eddies” in the flow field. As these disturbances gather energy from the mean flow, they begin to spawn
smaller disturbances or eddies which, in turn spawn even smaller eddies. This process ends because,
eventually, the eddies reach a size for which viscous effects become important and the very small eddies
are damped out by viscosity. Eventually, the spectrum of spatial or temporal eddy sizes reaches a “fully developed” state in which energy is fed from the mean flow into large eddies and then continually cascades down to smaller and then smaller eddies eventually reaching a size at which viscosity becomes important
and damps out those small eddies. In this fully-developed state the disturbance energy for any one size of
eddy becomes relatively constant though it can, of course, continue to change with the flow conditions.</blockquote>
### To Do
