MoorDyn: total horizontal force at anchor

Wind & Water Computer-Aided Engineering Software Tools
1

Hi,
I am using OpenFAST for a FOWT, with MoorDyn for the mooring dynamics - with a pyFAST wrapper to launch and postprocess a number of load cases.
To support an anchor design, it would be useful to have the total horizontal force acting at the anchor point, rather than the total tension or the 3 components of the tension at anchor point.
I know that it would be a simple matter of doing sqrt(force_x^2+force_y^2), but I was wondering if there is a way to output directly this value in MoorDyn, since I’m working with 400-500 simulations, and therefore this will add a further postprocessing step.

I suspect there is no such option, but I am asking just in case, and I suppose this is a question for @Matthew.Hall .

Kind Regards

Maurizio

2

Hi Maurizio. You’re right that there isn’t such an option right now. It’s a good point that it would be useful for efficient outputs when running many simulations. Maybe we can add it as an available output channel in the future.
Best,
Matt

3

Many thanks, @Matthew.Hall .
One quick question.
I always took for granted that, Point 1 is defined in the MoorDyn input file as an anchor point (i.e. fixed), x is aligned with the global platform x axis, y with the global y axis, and z with the global platorm z axis (i.e., vertical, positive pointing upward).
But, I cannot find a place where this is confirmed in the MoorDyn readthedocs: Link.

Also, what is the correct nomenclature to get the 3 components of the forces at anchor point? I tried:

  • CON1FX, CON1FY, CON1FZ and seems to work, but not included as possible output nomenclature in MoorDyn v2 lin above? Are they still the right way to get these components at anhor point? And aligned with global x,y,z axes?
  • POINT1FX, LINE1AFX, LINE1FXA, LINE1N0FX - no one work.

Many thanks