An overview of NACA 6-digit airfoil series characteristics with reference to airfoils for large wind turbine blades

Conference paper (2009)

Authors

Department
Aerospace Design, Integration and Operations (Aerospace Engineering) (TU Delft)
Copyright: © 2009 W.Timmer; American Institute of Aeronautics and Astronautics
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Published Date

31-12-2009

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Source:

47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 5-8 January 2009, Orlando, Florida; AIAA 2009-268

Faculty

Aerospace Engineering

Department

Aerospace Design, Integration and Operations

Abstract

This paper investigates the NACA 63 and 64 6-digit series of airfoils tested in the NACA LTPT in view to verify the RFOIL calculated airfoil characteristics for high Reynolds numbers. Some anomalies in the zero-lift angles of 15% and 18% thick airfoils from these series are identified, both in the airfoil clean case and in case of wrap-around roughness. It is found that RFOIL predicts the maximum lift coefficient at a Reynolds number of 3 million well, but consistently under predicts the Cl,max for Reynolds numbers of 6 and 9 million. It is, however, based on other comparisons at high Reynolds numbers unclear if this is due to an inability of the prediction code or to a deviation in the test results. The drag coefficient is under predicted with about 9% for a wide range of airfoils and Reynolds numbers. Due to wrap-around roughness the maximum lift coefficient decreases with 18% to 20%.