Better Ships, Blue Oceans’ to make ships cleaner, smarter and safer and to contribute to a sustainable use of the seas. Linking renewable energy, zero emission shipping and floating islands.

In the last decade, several mooring line failures have been reported for offshore structures in the North Sea. Such failures mostly occurred in severe sea states and are believed to be due to overloading of the mooring line loads. These failures showed the need to improve the methods and procedures in predicting the wave loads in harsh environments. The wave drift forces are especially important as they are a key parameter in the design of the mooring system. However, they tend to be underestimated by linear potential-flow based methods, which are still the work-horse design tool in the offshore industry. Model testing can be used to assess the wave drift loads and calibrate the numerical tools, but they are usually only performed in the final stage of the design.
In their research project Frédérick Jaouën, Arjen Koop, Tim Bunnik showed that MARIN’s in-house CFD code ReFRESCO is able to accurately calculate the wave drift loads on semi-submersibles in steep waves. This includes the prediction of the non-quadratic nature of the wave drift forces, which cannot be predicted by potential-flow based tools. The numerical results were validated based on the model tests performed on the
Stena Don platform in 2018. MARIN wishes to thank Stena for supporting us in this research project, and therefore contributing to our mission: Better ships, Blue oceans.
Interested in optimizing your design by minimizing the drift loads? Contact Frédérick Jaouën.

Improved design methods for wave impacts on offshore wind turbines.