Dear Hamid,
I’m not exactly sure why you are running into trouble. One thing that can cause problems is if the pre-curve and pre-sweep are not defined smoothly in BeamDyn, the local curvature can be very large, which may lead to numerical problems and result in either of the two errors you’ve reported. Just so you know, the initial local curvature of the blade (before loading is applied) is derived by fitting cubic splines through the key points. So, if the key points do not form a smooth curve, the splines could introduce “kinks” that would increase the curvature dramatically, and likely cause numerical problems.
To check for any problems with the NREL 5-MW model, I took Test26 and added a small upwind precurve to the blade. Basically, I changed kp_xb in BeamDyn from zeros to a quadratic function from 0 m at the root to -1 m at the tip, likewise for BlCrvAC in AeroDyn. Please find the updated BeamDyn primary and AeroDyn blade input files attached, if you want to run the model yourself. Rerunning Test26 with these change runs as expected.
Just FYI: the static analysis option of BeamDyn is not available when BeamDyn is coupled to FAST. I don’t believe this is currently checked, but in the next release, we’ll add a check to trigger an error if static analysis is selected in a coupled FAST-BeamDyn simulation.
Best regards,
NRELOffshrBsline5MW_BeamDyn_WithUpwindPrecurve.dat.txt (7.42 KB)
NRELOffshrBsline5MW_AeroDyn_blade_WithUpwindPrecurve.dat.txt (4.17 KB)