Making a WAMIT File

[Arbu-GoodCitizen]

Dear All,

I'm an undergraduate student that trying to used OpenFAST for the first time and i'm working on my undergraduate thesis. My thesis topic is about analysing the effect of pre-tension to the power output of OC5 DeepCWind Semisubmersible in vary load condition. And im trying to figuring out about:

1. Is the second order force will effecting the FOWT rotational movement that significantly? and how significant it will be to the rotation?
2. how can i make the WAMIT file for wave heading besides 0 degrees?

Thank you in advance,
Arbu

[jjonkman]

Dear @Arbu-GoodCitizen,

Here are my responses:

1. Second-order difference-frequency hydrodynamic loads can impact the resonant response of the rigid-body modes of floating offshore wind turbines, including motion of the floater-pitch and -roll modes. This effect was studied extensively within the IEA Wind Task 30 OC5 Phase II and OC6 Phase I projects and I suggest reviewing results from these Phases for more insight, e.g., see: https://www.sciencedirect.com/science/article/abs/pii/S0960148122000635.
2. NLR has only provided the full 2nd-order QTF from WAMIT for the OC4-DeepCwind semisubmersible only for the zero-degree wave heading. The potential-flow solution from WAMIT (or equivalent) must cover the full set of wave directions you intend to simulate in HydroDyn. You'll have to run WAMIT (or equivalent) to generate the 2nd-order QTFs covering the wave directions you wish to simulate in HydroDyn.

Best regards,