Thèse - Modelling free-surface flows of yield-stress fluids. Application to natural hazards

Description :
Context :
This offer is part of project YIELDGAP, an Innovative Training Network (ITN – Marie Slodowska Curie action) funded by EU, involving 9 academic and 5 industrial partners from 7 European countries. The ITN is dedicated to a better understanding of yield-stress fluids, from fundamental systems to industrial and geophysical applications, using experimental and modelling approaches. It will foster a multi-disciplinary and intersectoral educational research framework, in order to comprehensively train 12 early stage researchers to PhD level.

Project summary :
Natural hazards as debris flows and avalanches involve free-surface flows of complex, yield-stress fluids. The ambitious objective of this PhD project is to develop new-generation depth-averaged models to simulate such phenomena, and overcome the limitations of current simulation tools used for hazard evaluation and disaster prevention. Instead of relying on empirical closures, consistent asymptotic methods will be used to directly integrate the complex rheological properties of the materials in the model. An original three-equation approach will be employed to represent the internal shearing of the flows and the possible coexistence between yielded and unyielded zones. A specific focus will also be put on better accounting for the role of inertia in strongly non-uniform zones. Well-posedness of the model will be ensured, and numerical implementation using accurate and robust numerical schemes will be achieved. The predictive capabilities of the new asymptotic model will then be assessed through cross-comparisons with both experimental data and direct numerical simulations performed using advanced simulation tools developed by YIELDGAP partners. For these comparisons, specific configurations involving strong interplay between inertia and rheological effects (dam breaks, etc.) will be considered.

Job description :
The successful candidate will be in charge of the following tasks :
− Development of a depth-averaged model for large-scale natural yield-stress fluid flows based on consistent asymptotic methods
− Implementation of the model in an optimized and parallelized numerical platform
− Running numerical simulation campaigns
− Participation to laboratory experiments
− Systematic cross-comparisons between numerical and experimental results

The work will be hosted at INRAE / ETNA research unit (Grenoble, France), under the supervision of Prof. Guillaume Chambon and Dr. Gaël Richard. The candidate will be enrolled in the doctoral program of University Grenoble-Alps. Mobility periods to KTH (Sweden), EPFL (Switzerland) and Patras University (Greece) are planned. The candidate will also have a chance to develop an active collaboration network with other groups and PhD students involved in YIELDGAP.

Profile requirements :
− Master degree (or equivalent) in engineering, physics or applied mathematics
− Solid background in mechanical modelling and fluid mechanics
− Previous experience in scientific programming and numerical simulations
− Basic knowledge in non-Newtonian fluid mechanics
− Spoken and written competences in English
− Aptitude for team working ; ability to work independently ; professional approach

As this is an ITN EU initiative with a mobility requirement, eligible candidates must not have lived, studied or worked in France for more than 12 months in the last 3 years before their recruitment.

How to apply :
Application files must include the following documents :
− CV including your relevant professional experience and knowledge
− Application letter with a brief description of why you want to pursue research studies, your academic interests and future goals, and how they relate to the proposed project
− Copies of diplomas and grades from previous university studies and certificates of fulfilled language requirements. Translations into English or French if the original document is not issued in one of these languages.
− Recommendation letters are welcome.

Reference :

Date de démarrage : 10 mars 2021

Durée :

Contacter :
INRAE
Guillaume CHAMBON
Domaine Universitaire BP 76 38000 Grenoble France
email : guillaume.chambon@inrae.fr
Téléphone : 04 76 76 27 66