Modeling Examples Demonstrating Reduction in Fatigue

Viewing Presentations

This page includes a number of tabs conforming to wind turbines (AWT-27, WP 1.5 MW and NREL 5 MW).  The AWT-27, WP 1.5 MW and 5 MW Onshore are all onshore wind turbines.  The NREL 5 MW wind turbine was also modeled offshore on a tower mounted to the seabed (OC3 Tripod) and on a floating, semi-submersible platform (OC4 Deepwind).  Links to NREL reports describing the background and performance of the various wind turbines are included.  The AWT-27 is a teetering, two-bladed turbine and the others are three-bladed turbines with rigid hubs.  In order to compare teetering and rigid hubs, the FAST Elastodyn data files were modified to yield a three-bladed teetering hub.  The software modifications required to do so are presented in the tab entitled Fast Modifications accessible by clicking the "View Details of Hub" on the home page.  For comparison, the two-bladed AWT-27 with teetering hub is compared to a two-bladed AWT-27 with a rigid hub. 

Comparisons were made with a mean wind speed of 12 m/s, with normal turbulence and no skew.  This wind speed was chosen because wind speeds below and above the rated wind speed will be shown.  Examples accessible on this web page were modeled using the same shaft tilt (-5°) for both the rigid and teetering hubs.  Presentations link together a series of slides displaying many FAST output variables.  Most of the slides have notes at the bottom providing a comparison of the fixed and teetering hubs.  Some of the slides are designated highlight slides and demonstrate the reduction in fatigue provided by the teetering hub.  By clicking the appropriate button at the bottom of any slide, one can view either all slides or highlight slides only.  One can also change the timeframe with choices of 30 seconds, 1 minute, 2 minutes, 3 minutes and all data.  Additionally, one can use the slider at the bottom of the graph to modify the timeframe to any desired range.  Finally, the plot order can be reversed in case the second graph obscures the first.