Preprocessing Hydrodynamic Properties for BModesJJ / OpenFAST of a floating substructure

Wind & Water Computer-Aided Engineering Software Tools
2

Dear Daniel,

Here are my answers to your questions:

  1. Correct.

  2. For hydro_M, you could use the hydrodynamic added mass from WAMIT (or in your case, AQWA) at a given frequency e.g. the zero-frequency limit.

  3. C^Hydrostatic_ij in the OC3-Hywind specification report only includes the buoyancy-related restoring; the body weight-related restoring is not included om C^Hydrostatic_ij, but should be included in the platform stiffness specified in BModes–see the following forum topic for more information: BModes : Input parameters about tower support subsystem - #2 by Jason.Jonkman.

  4. Correct, MoorDyn cannot currently export the mooring stiffness matrix. You could use MAP++ or an equivalent tool to derive this.

  5. Without modification of the source code, HydroDyn cannot directly output the 6x6 added-mass matrix associated with strip-theory (Morison) members. And HydroDyn does not intrinsically form the 6x6 hydrostatic restoring matrix for strip-theory members, but instead, this restoring matrix is specified via the 6c6 AddCLin matrix input to HydroDyn.

I hope that helps.

Best regards