I am currently looking into the diffraction analysis for TLP floating type structures as a part of my thesis. For validation method, I am recreating the sum QTF plots shown in The Effects of Second-Order Hydrodynamics on a Semisubmersible Floating Offshore Wind Turbine: Preprint (nrel.gov), where the analysis is done for the UMaine TLP.
In this document, it was mentioned that the difference frequency QTF’s are wrong due to some convergence issue, but that there was no issue found with the sum frequency QTF. However, in the diffraction analysis that I have done, using both OrcaWave and Hydrostar, show completely different results (see OrcaWave results in figure below). My question therefore is, if the results shown in the paper are wrong and if there has been a follow up on this topic?
With kind regards,