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Title:
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Dynamic inflow: yawed conditions and partial span pitch control
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Author(s):
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Published by:
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Publication date:
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ECN
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1995
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ECN report number:
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Document type:
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ECN-C--95-056
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ECN publication
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Number of pages:
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Full text:
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237
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Download PDF
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Abstract:
The objective of the project was to further validate the engineeringmodels, which have been developed in the JOULE 1 project: 'Joint
Investigation of Dynamic Inflow Effects and Implementation of an Engineering
Method'. These models were developed to describe the wake induced
unsteadiness and non-uniformity in the rotor inflow, which occur at full span
pitching variations, coherent wind gusts and yawed conditions. The further
validation of these engineering models was based on full scale measurements
on the Dutch WPS-30 turbine and the German Uniwex turbine, wind tunnel
measurements and comparison of results with advanced free wake methods. By
combining the JOULE 1 and JOULE 2 results, much insight was gained in dynamic
inflow phenomena. In several measurement campaigns on turbines which were
exposed to fast (full span) pitching transients or yawed conditions, dynamic
inflow effects were clearly apparent in the mechanical loads and a general
validation of the dynamic inflow models was possible. It was shown that
dynamic inflow effects at pitching transients become more important with
increasing size and pitching speed of the turbine. Dynamic inflow effects at
yawed conditions become more significant with increasing loading and tip
speed ratio. A second objective of the project was to extend the dynamic
inflow engineering methods for partial span pitch conditions. The validation
of these models was based on measurements on the Howden Richborough turbine
and calculational results from the advanced free wake methods. It is found
that dynamic inflow for partial span pitch control is less significant. As
final conclusion it can be stated that the newly developed engineering
methods predict the dynamic inflow effects well. This appeared to be true for
a large range of rotor sizes and operational conditions. Therefore it is
recommended to replace the steady equilibrium wake models in aeroelastic
codes, by one of the engineering methods from the present projects. 64 figs.,
11 tabs., 16 refs., 14 appendices
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