ECN publication
The Latest Results on Experimental Wind Turbine Aerodynamics
Boorsma, K.; Schepers, J.G.; Gomez-Iradi, S.; Madsen, H.A.; Sorensen, N.; Shen, W.Z.; Schulz, C.; Schreck, S.
Published by: Publication date:
ECN Wind Energy 31-3-2014
ECN report number: Document type:
ECN-M--14-018 Conference Paper
Number of pages: Full text:
18 Download PDF  

A selection of results from IEA Annex 29 Mexnext on analysis of wind tunnel measurements is presented. A convincing example illustrates the importance of detailed aerodynamic measurements. The influence of MEXICO blade shape deviations between design and manufactured geometry was assessed by scanning the blade geometry and performing comparative CFD simulations with this geometry. Generally speaking the differences between the results for design and scanned geometry do not justify the differences observed between experiments and computations A comparison between calculations and unexplored measurements from the famous NREL UAE PHASE VI experiment at a relatively high rotational speed is performed. It was found that as long as prescribed airfoil data is used, a good agreement exists between lifting line code results. The tip effect remains difficult to predict, although it is questioned in how far the limited blade aspect ratio is representative for large commercial wind turbines. CFD RANS simulations generally perform better in this respect, although separated flow features remain a challenge for these models as well. Preparations for a second experiment on the existing MEXICO test rig are discussed. New configurations will be tested and new apparatus including an acoustic array will be used, by which an even higher quality data set can be assured than the first data set. A standstill test of the MEXICO blades in the Delft Low speed tunnel allowed to determine an appropriate roughness configuration and to make sure that the blades and their data acquisition are in good shape for the New MEXICO campaign.

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