Dear Jason,
You are right: without aerodynamics loads everything matches.
As you observed, by carrying out an onshore test I noticed that using the Control Torque I obtained a right Mx_tow=TwrBsMx (output in OutData), while with RotAeroMx the outputs did not return.
So, I also tried using Mx_nac=CntrTrq. However, both using RotAeroMx and CntrTrq I still have this error on the resulting Mx, the difference is very small between the two cases (as you can see in the following figures, for y and rx).
At this point I don’t know if the fact that everything goes back in the absence of aerodynamic loads means that the problem is in the Mx at the base of the tower: in the absence of aerodynamic loads, in fact, there are lower displacements and speeds, which could make less visible a error already present, which is instead enhanced in the presence of aerodynamic loads.
As already said, however, I have hydrodynamic loads and moorings identical to the FAST outputs, the restoring moment is a simple formula, which I have already verified several times, finally the non-linear loads have a very low contribution compared to the other loads.
Excluding these terms, and taking into account that the mass matrix should be correct, the problem if it is not in the aerodynamic loads is in some further contribution to those listed, which however does not seem to me to exist.
Best regards,
Lorenzo