Reply To: AQWA: Hydrodynamic response error

[S.S.S.ShankaVasuki]

Yes, the relative motions may be too big. What can be the reason for this? is it just due to the mass and inertial properties of the system? or anything else?

Also I tried to run the Frequency statistical analysis with the jonswap spectrum with Hs = 1m and the I also added all the connections as used in the reference article with all ball&socket connections as shown in the figure below. The Pitch RAOs seems to match better than the RAOs from the diffraction analysis as shown in the plots below. 

So, I wanted to know a few things:

1. How is the HR analysis giving errors whereas the frequency statistical analysis works without any errors?
2. I observed that the Pitch RAOs match well but other RAOs such as Roll and yaw dont match well. Does that mean there is something wrong in the model??
3. Also I get the info that " DAMPING FOR SOME FREEDOMS IS VERY SMALL VALUE SET TO NOMINAL 0.5% CRITICAL." . I tried also adding additional damping matrix in the surge direction to a large number, but still in the .LIS file, the percentage of critical damping still says 0%. So this value doesnt change irrespective of any high number I give in the additional damping matrix. Why is it so?

Can you please let me know the answers to the above questions.

Thanks!