Influence of wave modelling on the prediction of fatigue for offshore wind turbines

Authors

  • H. F. Veldkamp,

    Corresponding author
    1. Vestas/Delft University Wind Energy Research Group, c/o Wind Energy Research Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, Netherlands
    • Wind Energy Research Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, Netherlands.
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  • J. van der Tempel

    1. Offshore Engineering/Wind Energy Research Group, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, Netherlands
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Abstract

Currently it is standard practice to use Airy linear wave theory combined with Morison's formula for the calculation of fatigue loads for offshore wind turbines. However, offshore wind turbines are typically placed in relatively shallow water depths of 5–25 m where linear wave theory has limited accuracy and where ideally waves generated with the Navier–Stokes approach should be used. This article examines the differences in fatigue for some representative offshore wind turbines that are found if first-order, second-order and fully non-linear waves are used. The offshore wind turbines near Blyth are located in an area where non-linear wave effects are common. Measurements of these waves from the OWTES project are used to compare the different wave models with the real world in spectral form. Some attention is paid to whether the shape of a higher-order wave height spectrum (modified JONSWAP) corresponds to reality for other places in the North Sea, and which values for the drag and inertia coefficients should be used. Copyright © 2004 John Wiley & Sons, Ltd.

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