Hi, I am running AeroDyn (through OpenFAST) for the case of a FOWT with the 5MW NREL reference WT, and I am looking at two outputs: RotThrust, and RtAeroFxh. If I understand these outputs well, they should be the aerodynamic load in the direction normal to the rotor plane, and the aerodynamic load in the direction along the hub-bound coordinate system’s x-axis (along the shaft). Is that correct? If so, I would think that RtAeroFxh should simply be RotThrust times the cosine of the angle between the two directions. However, the results I am getting show no such relation. Could you please clarify (or point me to the right sources) the definitions of the particular coordinate systems, and the angles conventions. I’d appreciate any hints.
The axis normal to the rotor plane is the axis of the shaft for rotor without teetering. Instead, the difference between AeroDyn output RtAeroFxh and ElastoDyn output RotThrust has been discussed several times on this forum, e.g., see the following forum topic: NREL 5-MW reference turbine - CP, CQ, CT Coefficients - #32 by Chenxu.Zhao.
Thank you very much for your reply and providing the link to the previous discussion, all is clear now.