Postdoctoral position (24 months) on the development of nonlinear wave models
Guillaume Ducrozet
Dear colleagues,
A full-time (24 months) postdoctoral position in ocean
engineering is open at Ecole Centrale Nantes (ECN – France).
This postdoctoral position will be dedicated to the development of
nonlinear wave models and a complete description is provided at
the end of this e-mail.
Would you be kind enough to disseminate the announcement to
possible interested candidates?
Thanks a lot in advance, and sorry for possible multiple postings.
Best regards,
Guillaume
--
Context
Ecole Centrale Nantes has a new postdoctoral position available within the framework of the WASANO project. The overall objective of this project is to establish reference procedures for the design of marine structures, which are expected to be part of the future of regulations at the international level. This will be achieved through the creation of an international consortium bringing together experts in their respective fields.
Marine and maritime sectors are of primary importance in the local industrial context of the 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 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 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, funded by the I-Site NExT initiative, intends to address the problem of an accurate and controlled description of extreme environmental conditions for ocean engineering. To overcome several identified scientific bottlenecks, the project intends to propose innovative methods to i) define the extreme sea states responsible of the ultimate responses of structures at sea and ii) reproduce them in water tanks or with high-fidelity numerical solvers. These will apply to environmental conditions in numerical simulations and physical experiments at the model scale.
Work description
The accurate and efficient modelling of deterministic nonlinear waves has been an active field of research in recent years, leading to the development of different dedicated numerical models. At Ecole Centrale Nantes (ECN), an expertise on pseudo-spectral models based on the High-Order Spectral (HOS) method has been developed for more than 15 years, leading to the release of two open-source solvers, widely used in the ocean engineering community, that are still managed by the research team: HOS-ocean and HOS-NWT [1,2].
Those two solvers have been carefully validated and have been used on numerous and diverse configurations. It can be considered as mature for research, R&D and industrial applications [3,4]. Specific modules (not always included in the open source released version) have been developed to address the problems of interest:
- Creation of a Digital Twin for wave tank facilities [4,5]
- Reproduction procedures in wave tanks in a deterministic [6] or stochastic way [7]
- Post-processing to analyze the emergence of rogue waves in a sea state [8]
The postdoctoral researcher is consequently expected to contribute to the development of a new package that groups all the expertise of ECN regarding nonlinear wave models. This includes the existing open-source codes as well as all the modules previously mentioned. The objective with this new package is to allow a user with only a basic knowledge on waves, to be able to perform simulations of the desired configuration in a consistent way (including choice of numerical parameters). This main objective relies on non-negligible programming / software development, which is consequently a strong pre-requisite. To assist him with this task, the researcher will benefit of the knowledge of colleagues and of a software engineer present in the team.
However, depending on the profile of the candidate, the content of the postdoctoral position can be adjusted from a subject more code-architecture/software-oriented to a subject focusing also on model development. Then, according to the progress of the work, the postdoctoral researcher will be able to work on:
- Deterministic reproduction methodologies: extension to short-crested seas and breaking sea states.
- Wave breaking characterization: use the available databases among the WASANO consortium (experimental wave tanks, stereo-video imaging in real ocean) to improve knowledge of the phenomenon, design new experiments to be carried on in ECN, etc.
- Inclusion of wind forcing in HOS nonlinear wave models.
Complementary tasks will be part of this
postdoctoral
position. This includes a contribution to the set-up and
organization of databases
relevant to the WASANO project. Those can be experimental or
numerical
databases on wave and wave-structure interactions. Finally, it
is expected that
the postdoctoral researcher contribute to the project
management.
The position is available for 24 months.
Objectives / Expected results
- Development of a package including the expertise in wave modelling of ECN
- Development of new capabilities for the package
- Database management
- Project management
- Work in a collaborative environment through the active participation to international consortia.
- Write project reports and deliverables in line with funding entity expectations
- Write scientific publications
Technical skills and knowledge
Required qualifications are related to:
- PhD in Ocean Engineering, Fluid Dynamics, Physical Oceanography or Applied Mathematics with background knowledge of wave mechanics
- Proficiency in a scientific language: Python, Fortran, C++
- Previous experience in development in a shared environment would be appreciated
- Experience in scientific computing and numerical analysis
- Interest in ocean engineering problems, including experiments and data analysis
- Knowledge of the marine environment appreciated
Personal qualities:
- Autonomous and dynamic
- Ability to interact with researchers working on numerous and varied research topics
References
[1] https://github.com/LHEEA/HOS-ocean
[2] https://github.com/LHEEA/HOS-NWT
[3] Ducrozet, G., Bonnefoy, F., Le Touzé, D., & Ferrant, P. (2016). HOS-ocean: Open-source solver for nonlinear waves in open ocean based on High-Order Spectral method. Computer Physics Communications, 203, 245-254.
[4] Ducrozet, G., Bonnefoy, F., Le Touzé, D., & Ferrant, P. (2012). A modified high-order spectral method for wavemaker modeling in a numerical wave tank. European Journal of Mechanics-B/Fluids, 34, 19-34.
[5] Suret, P., Tikan, A., Bonnefoy, F., Copie, F., Ducrozet, G., Gelash, A., ... & Randoux, S. (2020). Nonlinear spectral synthesis of soliton gas in deep-water surface gravity waves. Physical Review Letters, 125(26), 264101.
[6] Ducrozet, G., Fink, M., & Chabchoub, A. (2016). Time-reversal of nonlinear waves: Applicability and limitations. Physical Review Fluids, 1(5), 054302.
[7] Canard, M., Ducrozet, G., & Bouscasse, B. (2022, June). Generation of Controlled Irregular Wave Crest Statistics in a Numerical Wavetank Using HOS-NWT Solver. In International Conference on Offshore Mechanics and Arctic Engineering (Vol. 85901, p. V05BT06A061). American Society of Mechanical Engineers.
[8] Ducrozet, G., Bonnefoy, F., Le Touzé, D., & Ferrant, P. (2007). 3-D HOS simulations of extreme waves in open seas. Natural Hazards and Earth System Sciences, 7(1), 109-122.
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Guillaume
DUCROZET Associate Professor in Ocean Engineering Deputy Director of LHEEA Lab. - Centrale Nantes and CNRS  1 rue de la Noë 44321 Nantes cedex 3 - France Office: D212 T: +33 (0)2 40 37 16 45 guillaume...@ec-nantes.fr |