Blade display / aerofoil profile data

Wind & Water Airfoils
1

Hi Jason,

We’re looking to build a blade display feature of our own, outside of OpenFAST. We’re using the IEA 15MW RWT as a representative test case. We are planning to use the aerofoil profile files to help generate display panels which will stack up to a fully 3D representation of the blade surface.

I have two questions which hopefully you may be able to answer.

  1. Some of the aerofoil profiles do not appear closed at the trailing edge i.e. there is a sizeable gap between the first and last points in the aerofoil coordinate points. See plot below, created for IEA-15-240-RWT_AF15_Coords.txt. Is there some reason for this? If we were to draw a blade profile based on the coordindates, it would have a flat/blunt side at the trailing edge, and this would look odd I feel.
  2. In the aerofoil coordinate files, is it safe to assume that the X-Coord, Y-Coord values are always in the following order: trailing edge to leading edge along the lower surface, and then leading edge to trailing edge along the upper surface?

Kind regards,
Aengus

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2

Dear @Aengus.Connolly,

Regarding (1), this is the characteristic of a flatback airfoil (sometimes used near the root of a wind turbine blade), which has a blunt trailing edge for structural efficiency.

Regarding (2), I’m actually not sure if AeroDyn has a specific requirement here, but I agree that is how the coordinate files for the IEA Wind 15-MW RWT are defined.

Best regards,

3

Thanks for those clarifications Jason, much appreciated.