Using FEAMooring for OC4 in OpenFAST

Wind & Water Computer-Aided Engineering Software Tools
1

Dear Dr Jonkman
I am trying to use the FEAMooring module for fatigue analsysi of tower base of OC4_Semi submersible platform, but the output for forces at the tower base is printed out as “NAN” in the output file, while I am using MoorDyn the output are printed correctly.

Do you have any idea what causes this error?

Thank you

Kind regards

Milad

2

Dear Milad,

We provided an FEAMooring input file for the OC4-DeepCwind semisubmersible model as an example in the OpenFAST r-test, but to be honest, this model has never been tested. I would guess that you may have to double-check that the FEAMooring inputs are set properly and you may have to play around with solver options (e.g., time steps) to get the model to run. I haven’t ran FEAMooring in a while, but if I recall correctly, OpenFAST may need to be compiled in double precision for FEAMooring to function properly.

FYI: We have generally been using MoorDyn in place of FEAMooring when needing to model mooring dynamics.

Best regards,

3

Thanks a lot