Fairlead tensions of Test24 not matching with hand calculation in still conditions

[Simon.Wiedemann]

Dear Jason,

where can I find the MooringSystemFD.txt for the OC3 Phase IV model you mentioned in your post?

Best regards,

Simon Wiedemann

@Jason.Jonkman

Dear Jay,

I’m not sure understand enough about what you are doing to answer, but here are a few comments:

• UnstrLen in MoorDyn should be set equal to the unstretched length of the mooring line, not the stretched length.
• *The tensions should not be the same between the 3 lines if the spar has displaced in any way (e.g. as a result of the overhanging weight of the rotor-nacelle-assembly).
• *I don’t know what theory you are using in your “hand calculation”, but does this calculation match the solution calculated by MAP++, which is solving the analytical quasi-static catenary equations?
• *I don’t know what each of the variables means in your spreadsheet, but from the data provided in the OC3-Hywind specifications report and corresponding MooringLineFD.txt file, the following values are reported at the undisplaced DISTANCE = 848.67 m (by linearly interpolating between 848.5 and 849.0 m):

TENSION = 911.1 kN
H.TENSION = 737.0 kN
SUSPL = 767.4 m. which corresponds to an unstretched length of line resting on the seabed = 134.8 m
TEN.ANCH = 737.0 kN

These values are a bit different than what you report in your spreadsheet and the result of your “hand calculation”.

Best regards,