For a standard pontoon after a 3DDIFF hydrodynamic run, if I export the damping matrix from the freq_res menu using matrices or equ_sum I do not see a change in the roll damping value irrespective of the wave steepness I use in the RAO command prior. The value is also the same as that generated from v_matrices in the Hydrodynamic menu. Therefore I conclude that it does not include the viscous component of damping contrary to my expectation. Please advise how do I include the linearised viscous component in the damping matrix reporting??
Hi John,
You are correct the v_matrices do not include tanaka damping. This has to do with the values in the matrices being linearized. Have you reviewed the b_keels sample file? There the changing in damping is done via a logarithmic decrement test.
I hope this helps.
Georgina Maldonado
Thanks Georgina for the confirmation, I will look at that example.
Kind Regards
JD