Questions about 5MW_OC3Mnpl_DLL_WTurb_WavesIrr

Wind & Water Computer-Aided Engineering Software Tools
10

Dear @Ran.Tu,

Here are my responses:

  1. When Nmodes = 0, your model has no Craig-Bampton modes at all. The Rayleigh damping method is described in the SubDyn documentation: 4.2.5.6. SubDyn Theory — OpenFAST v3.3.0 documentation.

  2. SubDyn will interpolate the diameter and thickness between the joints, but will not allow material properties to change between the two joints. The unique diameter and thickness at each joint are specified directly.

  3. I provided zero-valued WAMIT data files in my post dated Oct 30, 2012 in the following forum topic: Questions about the HydroDyn Module. You can now also specify AddCLin without specifying WAMIT data by setting PotMod = 1 with ExctnMod = RdtnMod = 0.

  4. When ElastoDyn, SubDyn, and HydroDyn are all enabled, (1) motions of the platform reference point are sent from ElastoDyn to SubDyn and the associated reaction loads are sent from SubDyn to ElastoDyn and (2) motions of the substructure are sent from SubDyn to HydroDyn and the associated hydrodynamic applied loads are sent from HydroDyn to SubDyn. Both the distributed hydrodynamic loads from strip theory and lumped loads from potential flow theory are sent from HydroDyn to SubDyn. To get the correct reaction loads from SubDyn, it would make the most sense to align the strip theory members in HydroDyn with flexible beam elements in SubDyn and to align the potential flow bodies in HydroDyn to joints connected by rigid links in SubDyn.

Best regards,