Missions

The focus is on the near-field flow dynamics and the flow-sediment-bathymetry interactions of hyperpycnal plumes, i.e., plumes induced by sediment-laden river inflows with a density higher than that of the receiving water body (lake, reservoir, ocean).
The near-field hydro-sedimentary processes control the fate of substances (e.g., sediments, nutrients, oxygen, contaminants) introduced by the river inflow, which is of critical importance in practical applications, e.g., water-quality modelling in lakes or sediment management in reservoirs. The current understanding of plume dynamics is limited to simple confined geometries, and flow-sediment-bathymetry interactions are not well understood because of a lack of field and laboratory data.
This project, in which the candidate will have to participate, will address three research questions for a broad range of confined and unconfined geometries:
(i) What are the characteristics and dominant control parameters of the flow processes?
(ii) What is the influence of sediment on these processes?
(iii) What are the dominant flow-sediment-bathymetry interactions?
This research project is based on laboratory experiments, field observations and numerical modelling. The experiments will be performed at the Coriolis Platform in Grenoble, which will be adapted for sediment-laden plumes. The implementation will be based on a preparatory experimental work . Results of both field and laboratory investigations will be generalized by numerical experiments with the SedFoam model.

Activités

The researcher will be in charge of performing numerical simulations of the Coriolis Platform experimental configurations using sedFOAM, in order to study the physical processes which govern flow-sediment-bathymetry interactions (see preliminary work of Shi et al 2022, 10.1029/2022wr032633).
Data analysis to evaluate turbulence and sediment fluxes and their characteristics, the feedback of the sediment laden plunging flow on the global dynamics and the synoptic velocity field as well as diagnostic tools for turbulent mixing and transport will also be part of the researcher's tasks. Regular meetings with the consortium researchers within the ANR PRCI (HARP) contract will permit comparisons of the experimental data with numerical/observational data (TUW,LEGI). The researcher may also participate to the experimental work at LEGI.

Compétences

- The candidate will need to master Computational Fluid Dynamics and turbulence-resolving simulations such as Large Eddy Simulation is required.
- An experience with python programming and openFOAM would be appreciated.
- A solid background in fluid mechanics with special focus on river flows and sediment transport, and theoretical/numerical tools is a prerequisite. Curiosity, autonomy and willingness to develop new skills are also necessary.
- Experience in using Linux environment and HPC facilities.
- Programming skills (python, C / C ++).
- Strong scientific writing skills are mandatory.

Contexte de travail

The Laboratory of Geophysical and Industrial Flows (LEGI) is a public research laboratory of the COMUE University of Grenoble Alpes. It is a joint research unit (UMR 5519) common to the National Center for Scientific Research ([CNRS]), Université Grenoble Alpes (UGA) and Institut Polytechnique de Grenoble (Grenoble INP), which gathers more than 150 people, including 60 permanent and as many PhD students and post-doctoral researchers.
Research activities in Fluid Mechanics and Transfer conducted at LEGI combine modeling, testing (more than 40 experimental facilities including large equipment), high performance numerical simulation (parallel computers, national computing centers ...) and the development of innovative flow measuring systems. These activities are related to numerous fields of application within environmental as well as industrial issues.
The successful candidate will work in the MEIGE team, Modeling, Experiments and Instrumentation for Geophysics and the Environment, gather all LEGI's research activities related to flows in natural environments: ocean, atmosphere, coastline.
The research conducted within the team focuses on describing, understanding and modeling the dynamics of these environments at small scales. This approach combines physical modeling approaches in the laboratory, in-situ measurement campaigns and theoretical and numerical modeling approaches.
The research activities of the team can be grouped according to three main themes (http://www.legi.cnrs.fr/web/spip.php?rubrique188&lang=fr:
- Boundary Layer processes and turbulence in geophysics
- Gravity waves : internal and surface waves
- Environnemental engineering

Contraintes et risques

No particular risk

Informations complémentaires

Desired degree :
PhD in multi-phase flows, granular flows or turbulence modeling.