I have experimental data (motions) of a floating wind turbine measured at a marker location and I want to compare them with the simulation results of the OpenFast numerical model. I just want to confirm if my understanding of the reference frame of OpenFast is correct or not.
In OpenFast, the motions corresponds to the “PtfmRef” point motions. it is defined at (0,0,0) in my numerical model, which is the centroid of the water plane area.
The X axis is pointing in the nominal downwind direction (same direction as the blowing wind), Y axis is pointing to the left and Z is pointing upward; I ight need to rotate the measured data axis as they could be different from the ones used in OpenFast.
I am planning to apply the same transformation matrix discussed here by replacing the center of gravity coordinates by the marker coordinates.
Thank you in advance for your help,
Dear Mohamad Hmedi,
Yes, that all makes sense to me.
Please see the recent discussion here about the coordinate system for a bit more precise definition: Wind-wave misalignment in OpenFAST - #9 by Ioannis.Voultsos.
Thank you again for your help.