**6. Conclusions**

In conclusion, in this work we propose an affordable methodology with the aim of the identification of non-linear viscous damping parameters. Results obtained are in line with the expectations and consistent with the physics and experience about the WEC device considered. The hi-fi CFD techniques could be performed one-time considering few cases (in this work three different initial conditions for the free decay). This first investment in terms of computational costs and effort can lead to the evaluation of those non-linear coefficients, related to significant physical phenomena. This identification provides an important enrichment of low-order models used for next design and analysis steps.

**Author Contributions:** Conceptualization, M.F. and P.C.; data curation, M.F., P.C., S.A.S. and G.G.; formal analysis, M.F. and P.C.; funding acquisition, G.B. and G.M.; investigation, M.F. and P.C.; methodology, M.F., P.C., S.A.S. and G.G.; project administration, S.A.S., G.G., G.B. and G.M.; resources, M.F., P.C., G.B. and G.M.; software, M.F. and P.C.; supervision, S.A.S., G.G., G.B. and G.M.; validation, M.F., P.C., S.A.S. and G.G.; visualization, M.F. and P.C.; writing—original draft, M.F. and P.C.; writing—review and editing, M.F., P.C., S.A.S. and G.G. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** Computational resources provided by hpc@polito (http://hpc.polito.it).

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
