진학프로석·박사 채용 접수 플랫폼

Context

Formed in 2016, the Joint Laboratory of Marine Technology (JLMT) is an industry–academia partnership between Centrale Nantes and Naval Group. Its mission is to combine academic research and industrial expertise to deliver innovations for Naval Group’s military shipbuilding applications. The collaboration aims to tackle the maritime industry’s key challenges while contributing to national goals in competitiveness and energy transition.

After a first extension in 2020, the partnership will continue beyond 2024 with an increased focus on hydrodynamics. The main objective of this research theme is to develop solutions that enhance ship stability and performance under extreme conditions.

As part of this effort, a new postdoctoral position on ship load evaluation is available at Centrale Nantes. The selected researcher will contribute to the development of a multi-fidelity modeling tool in close collaboration with Naval Group.

Work description

A ship needs to withstand local and global loads that occurs when sailing in irregular waves. Shipyards usually rely on rules or guidelines, which are written by classification companies thanks to empirical experiences and computations on a large number of ships. Another approach is to perform calculations to assess the loads on one specific ship. The difficulty is then to identify the relevant input conditions to test. There are several ways to do, as example though design waves or through a Monte Carlo approach in irregular waves. Because of the computational burden it is not practical to do this entirely with CFD. Some techniques have been developed recently to compute design waves with a multi-fidelity method [1]. However, this is not straightforward in case of complex physical phenomenon as impacts. The current project aims to develop a multi-fidelity method for a Monte-Carlo analysis. First critical events should be identified in irregular waves with a “fast” seakeeping code, then the same wave field is generated in a high-fidelity CFD wave structure interaction computation around this event.

The objective is to develop a multi-fidelity tool based on one system-based ship simulation tool “Xdyn” [1] and one CFD solver developed within the OpenFOAM framework [3].

The methodology is, for a given ship and a given environment:

• • First, run a simulation with Xdyn in irregular waves. Irregular waves will be provided by the HOS potential solver [4]developed at Ecole Centrale Nantes.
• • Identify, within the previous simulation, the critical events for local or internal loads based on indicators and thresholds that will be defined conjointly with Naval Group.
• • Extract an initial condition for the ship simulation in the CFD framework (starting before the event).
• • Reproduce the event with the CFD solver and correct the load.

Wave generation in the CFD solver using HOS-Ocean and HOS-NWT is already effective [5] [6].

The most important aspect is the development of the complete tool, but some other topics will be considered, among others:

• • Choice of the “good” indicator and of the associated threshold to identify the critical events,
• • Study on how to release the free motion in the CFD computation or how to force the motions if it is necessary,
• • Compute the local loads and the internal loads (a methodology already exists),
• • Validate the CFD code for impacts and develop the best numerical setup for this (limiters, boundary conditions, free-surface modeling, etc…).

The tool will then be tested on a practical case of interest.

The position is available for 24 months.

Objectives / Expected Results

• • Development of the combined tool,
• • Validation of the CFD code for impact cases,
• • Application/demonstration of the developed tool,
• • Diffusion of the results in international conferences and top-ranked journals,
• • Work in a collaborative environment through active participation in a national consortium.
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References

1. • Dermatis, A., Lasbleis, M., Kim, S., De Hauteclocque, G., Bouscasse, B., & Ducrozet, G. (2025). A multi-fidelity approach for the evaluation of extreme wave loads using nonlinear response-conditioned waves. Ocean Engineering, 316, 119919.
2. • https://github.com/sirehna/xdyn
3. • Descamps, T. (2022). Numerical analysis and development of accurate models in a CFD solver dedicated to naval applications with waves (Doctoral dissertation, École centrale de Nantes).
4. • https://gitlab.com/lheea/HOS-Ocean
5. • 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)
6. • Descamps, T., Elsayed, O., Bouscasse, B., Lasbleis, M., & Gouin, M. (2025). Validation and verification applied to CFD simulations of ship responses to regular head waves with forward speed. Ocean Engineering, 320, 120177.