WASANO project

Marine and maritime sectors are of primary importance in the local industrial context of Nantes regional area. In those fields, efficient and sustainable management of activities at sea (security, energy efficiency, etc.) is naturally an objective, so as supporting the development of Marine Renewable Energies. At the local, national and international levels, those sectors are still facing several challenges, due to the complexity and severity of the ocean environment.

The most prominent one is probably to account for the extreme wave conditions in the design of the marine structures. Those environmental conditions as well as the induced responses exhibit complex physical processes. In this context, the present procedures for the evaluation of the extreme responses are known to be inaccurate. This induces the regulations of classification societies to consider large safety factors that may be inadequate in some conditions.

The WASANO project intends to address the problem of an accurate and controlled description of extreme environmental conditions for ocean engineering. To overcome the several identified scientific bottlenecks, the project intends to propose innovative methods to:

• define the extreme sea states responsible of the ultimate responses of structures at sea
• reproduce them in water tanks.

These will apply to environmental conditions in numerical simulations and physical experiments at model scale (Centrale Nantes Ocean tanks).

Due to the large extent of the scientific themes involved in the project (statistics, fundamental physics, experiments, numerical modeling, etc.), there is a need in bringing together experts in their respective fields. The WASANO project will create a large international consortium in view of establishing reference procedures, which are expected to be part of the future of regulations at international level.
This would be a significant result for the future of the ocean engineering industry in order to:

• reduce costs associated to a too large safety margin
• reduce risks associated to the extreme responses of marine structures.

This international partnership involves for now 14 world-renowned international universities as well as 4 industrial partners. The latter will ensure the adequacy between the research developed and the effective needs of the ‘Industry of Tomorrow’.

The WASANO project in a few figures :

• 3 test campaigns in ponds
• 5 theses involved in the project, including 1 dedicated to the project between 2022 and 2025
• 1 post-doc dedicated to the project
• 3 Master's courses

• Athanasios DERMATIS (PhD Student, École Centrale Nantes), began his PhD at LHEEA in September 2022. He works towards the development of a methodology to determine the underlying wave sequences that induce extreme responses on marine structures, using reliability analysis methods. The objective of this method is to provide an alternative to the Monte Carlo Simulations for obtaining converged short-term response statistics through high-fidelity simulations or experiments of short duration wave episodes.
• Florian HULIN  (Post-doc, École Centrale de Nantes), began a post-doctoral contract in February 2024. He defended his PhD thesis in 2024 at Ifremer Brest. His thesis was dedicated to the hydrodynamic forces generated by the impact of breaking waves on floating offshore wind turbines. He now works on facilitating the implementation of  different wave generation procedures within the potential flow solvers developed by ECN. The objective is to group the expertise of ECN regarding non-linear wave models and wave generation in a single package.
• Alessandro GUERRI (MSc student, École Centrale de Nantes), began his internship at the LHEEA laboratory in February 2023. The objective of his thesis is to conduct a comparison between three different numerical methods for nonlinear wave propagation: HOS-NWT, developed by École Centrale de Nantes (ECN) and based on pseudo-spectral methods; OceanWave3D, developed by the Technical University of Denmark (DTU) and based on finite differences and IITM-FNPT2D, developed by the Indian Institute of Technology (IIT) Madras and based on finite elements. The accuracy of the solvers is evaluated with respect to experimental data from the LHEEA ocean wave tank.

• Kim, S., Bouscasse, B., de Hauteclocque, G., Ducrozet, G. and Lasbleis, M. (2024). Experimental analysis of extreme wave loads on a containership. Ocean Engineering.
  • https://doi.org/10.1016/j.oceaneng.2024.118031
• Dermatis, A., Leroy, V., Ducrozet, G., Bouscasse, B., Delacroix, S., Bredmose, H., and Bingham, H., 2024. “Stochastic Prediction of the Extreme Responses of a Floating Offshore Wind Turbine Using Response-Conditioned Waves”. Proceedings of the ISOPE 2024 34th International Ocean and Polar Engineering Conference. June 16-21, 2024
  • https://hal.science/hal-04631274v1
• Bouscasse, B., Dermatis, A., Ducrozet, G., de Hauteclocque, G., Lasbleis, M., 2024. Assessment of nonlinear loads and motions through response-conditioned waves: Practical applications and limits, Proceedings of the 43rd International Conference on Ocean, Offshore and Arctic Engineering. June 9-15, 2024
  • https://doi.org/10.1115/OMAE2024-128825
• Kim, Y. J., Canard, M., Bouscasse, B., Ducrozet, G., Le Touzé, D., & Choi, Y. M. (2024). High-Order Spectral Irregular Wave Generation Procedure in Experimental and Computational Fluid Dynamics Numerical Wave Tanks, with Application in a Physical Wave Tank and in Open-Source Field Operation and Manipulation. Journal of Marine Science and Engineering, 12(2), 227.
  • https://doi.org/10.3390/jmse12020227
• Wang, Y., & Ducrozet, G. (2024). Evaluating instantaneous crest phase speed in multi-directional seas through Hilbert transform. 39th International Workshop on Water Waves and Floating Bodies, Scotland.
• Aertsens,T., Ducrozet, G., Toffoli, A., Monbaliu, J. (2023). Two-Sided Wave Generation in a High-Order Spectral Numerical Wave Tank. Proceedings of the ASME 2022 42nd International Conference on Ocean, Offshore and Arctic Engineering. June 11–16, 2023.
  • https://doi.org/10.1115/OMAE2023-100850
• Ducrozet, G., Bouscasse, B., Bonnefoy, F., Leroy, V. (2023). Methodology for the Integration of Experimental and Numerical Fluid Dynamics in the Study of a Floating Body Such As a Wind Turbine Subjected to Environmental Loads. Proceedings of the ASME 2022 42nd International Conference on Ocean, Offshore and Arctic Engineering. June 11–16, 2023.
  • https://doi.org/10.1115/OMAE2023-104676
• Aliyar, S., Ducrozet, G., Bouscasse, B., Sriram, V., & Ferrant, P. (2022). Efficiency and accuracy of the domain and functional decomposition strategies for the wave-structure interaction problem. Ocean Engineering, 266, 112568.
  • https://doi.org/10.1016/j.oceaneng.2022.112568
• Davison, S., Benetazzo, A., Barbariol, F., Ducrozet, G., Yoo, J., & Marani, M. (2022). Space-time statistics of extreme ocean waves in crossing sea states. Frontiers in Marine Science, 9.
  • https://doi.org/10.3389/fmars.2022.1002806
• Canard, M, Ducrozet, G, & Bouscasse, B. "Generation of Controlled Irregular Wave Crest Statistics in a Numerical Wavetank Using HOS-NWT Solver." Proceedings of the ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering. June 5–10, 2022.
  • https://doi.org/10.1115/OMAE2022-79880
• Choi, Y., Bouscasse, B., Ducrozet, G., Seng, S., Ferrant, P., Kim, E. S., & Kim, Y. (2022). An efficient methodology for the simulation of nonlinear irregular waves in computational fluid dynamics solvers based on the high order spectral method with an application with OpenFOAM. International Journal of Naval Architecture and Ocean Engineering, 15, 100510.
  • https://doi.org/10.1016/j.ijnaoe.2022.100510

• Numerical Wave Tanks : Comparison of different nonlinear models, Alessandro GUERRI' Master thesis, under the supervision of Guillaume DUCROZET, Ecole Centrale de Nantes, August 2023
  • https://hal.science/hal-04322647

First Experimental Campaign: Unidirectional sea states controlled at target positions

 

 

• Period: February-March 2022
• Objectives: Control of the wave spectrum and the wave height/crest statistics in different positions along a wave tank
• Experimental Facility: Towing Tank of Ecole Centrale Nantes

 

Second Experimental Campaign: Short-crested sea states

• Period: July-August 2023 and October-November 2023
• Objectives: Assessment of the spectra and statistics of multidirectional sea states
• Experimental Facility: Ocean Engineering Tank of Ecole Centrale Nantes