I have two questions regarding MoorDyn. My questions are:
- What version of MoorDyn does openFAST v2.4.0 use?
- How are hydrodynamic forces calculated in this version?
I could only find a manual for version 1.00.02, but I understand there are newer versions of the program. That manual states the following:
"The formulation supports inclusion of wave kinematics in the hydrodynamic force calculations, but that functionality is currently disabled in the absence of a standardized method for receiving wave kinematics data in coupled simulations. In the FAST v8 version, hydrodynamic loads will eventually be handled externally by coupling with HydroDyn (in the current version, hydrodynamic forces are calculated assuming still water).
I am wondering if this update was made: was MoorDyn was coupled with HydroDyn to calculate hydrodynamic loads?
MoorDyn in all the versions of OpenFAST released to date uses the same hydrodynamic formulation as detailed in the original 2015 Ocean Engineering paper, and without inclusion of wave kinematics. A long-awaited update to MoorDyn “version 2” is planned for the next OpenFAST release, v3.1.0. This version will still use the same hydrodynamic formulation except that there will be an option to include wave kinematics. More information will be provided in the MoorDyn documentation at that time.
To answer your first question, OpenFAST v2.4 includes MoorDyn with a version number of v1.01.02F. MoorDyn has some online documentation at moordyn.readthedocs.io. The documentation is not currently very good because there are several different MoorDyn improvements floating around waiting to be merged into the main OpenFAST code. Once that happens, the input file format and modeling will be standardized, and I will get the documentation updated to clearly describe the latest version.
Thanks for clarifying Matt!