About WAMIT model for 5MW OC3 Hywind

Wind & Water Computer-Aided Engineering Software Tools
5

Dear Yu Lei,

Here are my answers to your questions:

  1. Actually, FAST’s HydroDyn module does not read WAMIT *.out files. Instead, HydroDyn makes use of distinct WAMIT files for distinct hydrodynamic quantities e.g. *.1 files containing the frequency-dependent added mass and damping from the radiation problem, *.3 files containing the frequency- and direction-dependent wave excitation loads from the diffraction problem, and *.hst files containing the restoring from the hydrostatics problem. WAMIT *.out files contain similar data, but stored in a different format.

  2. For floating systems, you should define the WAMIT geometry at the equilibrium position of the floater in the heave (vertical) direction i.e. where the external buoyancy from displaced water balances with the weight of the system (including the weight of the rotor-nacelle assembly, tower and substructure) and mooring system pretension.

I hope that helps.

Best regards,