PTDM implementation

Dear @Emanuel.Rergis,

I’m glad you got your simulation to converge. Please note that reducing DT by a factor of 2 would be a similar computational expense to increasing NumCrctn from 0 to 1 and reducing DT by a factor of 3 would be a similar computational expense to increasing NumCrctn from 0 to 2. That said, it is sometimes beneficial for the coupling algorithm to increase NumCrctn rather than reduce DT.

Regarding your additional questions:

  1. There is no hard limit on WaveTMax, but eventually you could run into memory allocation issues if WaveTMax is very large.
  2. I’m not sure I understand why want to run such a long simulation of 24 hours. We typically recommend running multiple seeds of shorter simulations (such as 24 simulations of 1 hour each) rather than one really long simulation.
  3. I agree that if WaveTMax is less than TMax, than the waves will repeat after WaveTMax. But the simulation start-up transients are a result of initialization of the model and do not start again if waves start to repeat.

Best regards,

Thank you very much, Dr. @Jason.Jonkman. I followed your advice and am now running a massive number of simulations. During this time, two questions arose in my mind:

  1. Would there be any shortcut I can take to run a Montecarlo simulation?
  2. Is there any way to see a sample of a Prescribed force/moment time series file? I would need this to create my “own TMD”, and I would like to explore if that’s feasible with this option. What can you advise?

Thanks a lot for your help.
Best wishes!!!
Emanuel

I’m not sure I understand your first question.

You can find an example OpenFAST model with a prescribed force/moment time series in the following r-test: r-test/glue-codes/openfast/StC_test_OC4Semi at main · OpenFAST/r-test · GitHub.

Best regards,