Forced motion imposed on a floater

Wind & Water Computer-Aided Engineering Software Tools
1

Good morning Mr Jonkman,
I am reposting this message that was sandwiched between already treated queries.

First of all, thanks for your past answer on the PropPot flag that made things clearer for me.

I have another query to run simulations with the semi submersible : to generate a forced motion on the floater, what is the proper way to proceed; I would think to put WAMITInputsMod = 2 and to give the following time series informations :

Column 1 : Time step value (s)
Columns 2-4 : Translational displacements along X, Y, and Z (m)
Columns 5-7 : Rotational displacements about X, Y, and Z [small angle] (radians)
Columns 8-10: Translational velocities along X, Y, and Z (m/s)
Columns 11-13: Rotational velocities about X, Y, and Z (radians/s)
Columns 14-16: Translational accelerations along X, Y, and Z (m/s2)
Columns 17-19: Rotational accelerations about X, Y, and Z (radians/s2)

Is it correct ?
Thanks in advance for your answer.
Best regards.
Florence Haudin.

2

Dear Florence,

Sorry, I must have missed your earlier post.

Yes, you could use the WAMITInputsMod=2 option from the standalone HydroDyn driver as your propose, but please be aware that this approach only applies to the potential-flow solution. The option 2 is is unavailable for the strip-theory solution (Morison members) without modification of the source code. Moreover, if you are asking because you are running cases for the IEA Wind Task 30 OC6 project, then please be aware that prescribing the platform motion from the standalone HydroDyn driver will allow you to calculate the time-varying hydrodynamic loads, but the platform body mass / inertia loads will not be considered in the response (you would have to add these effects separately).

Best regards,