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 applications in military shipbuilding. 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” [2] 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.
•	
Technical skills and knowledge
Required qualifications are related to:
•	PhD in Applied Mathematics or relevant field of engineering such as 
Fluid Dynamics, Inverse Problems, Signal Processing, etc.
•	Interest in ocean engineering problems
•	Knowledge in seakeeping modelling of a ship or floating structure
•	Proficiency in a scientific language: Python, Fortran, C++
•	Knowledge in Computational Fluid Dynamics
Other skills will be appreciated for this position:
•	Understanding of the maritime environment 
•	Scientific computing and numerical analysis
•	Development in a collaborative environment
•	Development of CFD code.

Personal qualities:

•	Autonomous and dynamic
•	Ability to interact with researchers working on numerous and varied 
research topics

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.