PhD title:
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Numerical modelling for the prediction of bank erosion due to river traffic: fluid-structure interaction and failure mechanisms
Description, context, objectives
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The banks of waterways (both natural and man-made) are subject to high hydraulic and hydrodynamic stresses due to the passage of boats and the associated water level fluctuations. The modal shift from roads to rivers has had a positive effect on greenhouse gas emissions associated with transport. However, this shift is accompanied by an intensification of river traffic on certain waterways, which can have an impact on ecosystems and infrastructures. In this context, the aim of waterway protection is to limit the use of artificial and costly bank protection solutions.
This raises the question of how to predict the long-term performance of river banks and waterway maintenance. At present, the "pragmatic" approaches used (simplified analytical formulations) struggle to provide a satisfactory account of the complexity of the physical phenomena at play at the bank and waterway level (bank erosion and stability, sediment transport of eroded material, etc.).
Understanding and modelling these phenomena, which are the combination of several multi-physical and multi-scale processes involving fluid flow (global in the waterway), its evolution (local) under the effect of the passage of a boat and its interaction with the bank, is crucial to provide predictive models for the evolution and behavior of waterways.
In this context, the aim of this project is to propose a coupled modeling strategy to monitor the evolution of the bank performance and to evaluate the implemented natural protection solutions. The results of this modeling will also be used to feed numerical models of sediment transport resulting from bank degradation.
For this purpose, the bank is considered as a porous medium subject to a fluctuating load corresponding to the hydrodynamic flow induced by navigation. As a boat passes by, the loading and saturation of the bank changes, leading to gradual degradation and eventual erosion. The transport of eroded solids causes changes in the morphology of the waterway, which in turn affects the hydrodynamic flow. The model used to estimate bank erosion must therefore be designed so that it can be coupled with a sediment transport model to estimate morphodynamic changes in the channel.
The objectives of this thesis are to:
• propose a robust numerical strategy for solving the nonlinear
the non-linear Richards equation forced by water level fluctuations;
• propose a strategy for coupling the previous tool with a numerical
tool for describing bank damage as a porous medium with variable saturation.
The work will conclude with a model validation phase based on in situ in situ and laboratory measurements carried out by the project partners (EPTB Saône, Institut Pprime).
Candidate profile and skills
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To successfully complete the project, you are expected to have :
• good knowledge of the mechanics of deformable media
• knowledge of fluid mechanics and flow modeling
• good numerical simulation skills, particularly in finite element methods
• good programming skills or, failing that, a pronounced interest in programming
• sufficient level of English for reading and writing technical and scientific documents, and for oral presentations.
Starting date: January 2025
Place of thesis work: Université de technologie de Compiègne, Laboratoire Roberval, France
Contract duration : 36 months
Possibility of additional missions: Possibility to obtain a «doctoral contract » allowing to teach 64hours/year.
Host laboratory: Laboratoire Roberval, Mécanique, Énergie et Électricité
Research team : Computational mechanics
Web site: https://roberval.utc.fr/
Material resources: The candidate will be provided with a computer and the software required for his or her research activity.
Human resources: The candidate will be immersed in the research teams of the Roberval laboratory and the CEREMA teams. At the UTC, he/she will benefit from the support of lecturers, PhD students and post-docs in the Digital Mechanics team. He/she will also benefit from the expertise and support of the CEREMA team.
Financial resources:The research project is funded as part of the ANR INFLUE project.
Work arrangements: The successful candidate will work mainly at the UTC, but will be able to travel to the CEREMA Compiègne premises (5min from the UTC) to benefit from the support of the CEREMA supervisors.
Regular weekly progress reviews with academic supervisors.
Progress reviews will also be organized in the presence of the various partners in the ANR Inlfue project (on a half-yearly basis).
Original results will be published in A-rank journals in the field.
The successful candidate is expected to participate actively in the scientific life of the laboratory.
Research project linked to the thesis: The thesis is part of the ANR (French national agency for research) Influe project.
National collaborations ANR Influe project partners: CEREMA, Institut Pprime, EPTB Saône, VNF
Persons to contact (further information or application) Delphine Brancherie : delphine.brancherie@utc.fr
Hassan Smaoui : hassan.smaoui@cerema.fr
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