ECN publication
Structural Pitch for a Pitch-to-vane Controlled Wind Turbine Rotor
Lindenburg, C.; Politis, E.S.; Hansen, M.H.
Published by: Publication date:
ECN Wind Energy 1-10-2004
ECN report number: Document type:
ECN-C--03-087 ECN publication
Number of pages: Full text:
71 Download PDF  


Within the European research project DAMPBLADE investigations were performed into wind turbine rotor blade structures with enhanced material- and aeroelastic damping properties. Within task 3.4 of this project 'Design application, sensitivity analysis and aeroelastic tailoring', investigations were performed into the influence of structural modifications of a rotor blade that improve the aeroelastic stability and fatigue loading.

These investigations were performed by CRES, ECN, and by Riso and focussed on the influence of  Strutural Pitch on the aerodynamic damping. Basis for these investigations was the RB70 rotor blade of Polymarin B.V., that was designed for a variable-speed pitch-to-vane wind turbine. The RB70 blade was modelled on basis of descriptions of several blade cross sections that were provided by WMC. Because the aerodynamic damping for the flatwise blade vibrations of pitch-to-vane controlled wind turbine is inherently positive, only the influence of Structural Pitch on the damping of the edgewise vibrations is reported.

From the calculations with BLADMODE, HAWCBladeStab, PHATAS, and Stab-Blade it follows that Structural Pitch can be used effectively to improve the aeroelastic response of rotor blade vibrations. The results from the time-domain code PHATAS did not show such a strong influence, while the results from the other aeroelastic analysis tools show quite similar trends for Structural Pitch. It was also shown that modelling of the steady deformed state does have an effect on the aerodynamic damping of the edgewise vibrations.

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