Environmental Engineering Reference
In-Depth Information
NREL Blind Comparison
4000
Measurements
Performance 1
Performance 2
Performance 3
Wake 1
Wake 2
CFD 1
CFD 2
CFD 3
Aeroelastic 1
Aeroelastic 2
Aeroelastic 3
Aeroelastic 4
3500
3000
2500
2000
1500
1000
500
0
0
5
10
15
20
25
30
Wind-speed(m/s)
Figure 15: Blind comparison of shaft rotor torque of various predictions against
measurement.
simulation (probably M. Hansen and T. Chaviaropoulus) were obtained. The
effort was still rather expensive: 3M cells and about 50 h CPU on a 4-processor
machine. Later Sørenesen [60] also introduced also transitional effects but with
limited success.
4.4 MEXICO
The European answer to the NREL experiment was a model experiment in con-
trolled conditions. The large-scale facility of DNW of
open section
was used [57]. A complete analysis is to be worked out within the new established
IEA Annex 29 MexNext , where scientists from several countries outside Europe
will also participate. Most important is the additional measurement of the velocity
fi eld by Particle Image Velocimetry (PIV).
2
95
.
×
95m
.
5 Aeroelastics
5.1 Generalities
Wind is transformed into forces by striking the solid structure of the blades. These
are manufactured by regarding them as aerodynamic devices. Lift, drag and pitch-
ing moment result from the combined fl ow of wind and rotating fl ow. These forces
now act ona fl exible structure. The interaction of aerodynamics and structural
mechanisms is called aeroelastics. As turbines become larger they necessarily
 
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