30-month Postdoc position in Fluid mechanics: Flow kinematics in transparent replicas of geomaterial samples using innovative 3D printing/molding techniques

RESEARCHER PROFILE: Postdoc / R2: PhD holders 
RESEARCH FIELD(S)1: Physics, Geosciences
MAIN SUB RESEARCH FIELD OR DISCIPLINES1: Fluid mechanics

JOB /OFFER DESCRIPTION 
The research unit RECOVER from INRAE is pleased to invite applications for a postdoctoral position dedicated to the experimental characterization and direct flow visualization in optically transparent porous media replicating as closely as possible the microstructure of real porous material and geomaterial samples scanned via X-ray tomography. The replicas will be obtained by elaborating innovative 3D printing and molding techniques. Achieving such transparent replica of real soil samples will allow for investigation of the transport processes in complex 3D porous microstructures. This postdoctoral position is fully funded by the ANR-23-CE51-0024 JCJC KiWiPoM.

Geomaterial are complex porous material presenting a wide diversity of structures that set the flow kinematic of any fluids through it. Understanding what drives and control the transport processes in porous media is thus crucial for a broad range of applications. Transport processes are characterized by investigating the flow velocity fields, which is usually performed using direct flow visualization techniques such as particle image velocimetry (PIV) or particle tracking velocimetry (PTV). Because of the opaque nature of porous media, direct flow visualization are usually prohibited within real soil microstructure, making flow kinematic characterization particularly challenging in 3D porous media. This project aims to tackle this experimental limitation by elaborating innovative 3D printing & molding techniques to replicate as closely as possible the microstructure of real porous material and geomaterial samples scanned via X-ray tomography. Lifting such technical barrier will pave the way for detailed investigations of porous media of increasingly complex microstructure, to fully characterize which microstructure features or heterogeneities set the flow kinematic and controls the transport processes in 3D porous media.

The 3D printing & molding techniques will revolve around sacrifical molding: the 3D pore network of a geomaterial sample scanned via X-ray tomography will be printed and used as a sacrificial mold with an optically transparent material (PMMA, or PDMS) for the surrounding solid phase. The interstitial pore network will then be removed chemically to obtain a transparent replica of the scanned sample. Similar approaches have been recently developed for additive manufacturing to create complex microfluidic channels using sugar as a sacrificial mold, or to create transparent brain arteries models in PDMS using water soluble resin. Adapting such approach to the field of geomechanics will not only unlock the challenging issue of opacity prohibiting direct visualizations in the porous media community, but also allow for a high level of control of the investigated microstructure, which will be useful to optimize transport processes through porous media by determining how local alteration of a microstructure may enhance transport processes. This promising approach yet requires rigorous tuning, as the technical feasibility strongly depends on the amount and quality of the interfaces through which the flow visualization is done. Homogeneity of the mold PMMA (or PDMS) is crucial, and will require precise tuning to allow for the use of refractive index matching techniques for flow direct visualization. The flow will then be characterized by reconstructing experimentally the 3D velocity field using successive scans of the flow velocity.

Website: https://mathieusouzy.wordpress.com/

TYPE OF CONTRACT: TEMPORARY / JOB STATUS: FULL TIME / HOURS PER WEEK: 38h40
APPLICATION DEADLINE: 28/02/2025
ENVISAGED STARTING DATE: 01/03/2025
ENVISAGED DURATION: 24-30 months
JOB NOT FUNDED THROUGH AN EU RESEARCH FRAMEWORK PROGRAMME

WORK LOCATION(S): UMR RECOVER, INRAE Aix-en-Provence, 3275 route de Cézanne, Le Tholonet (France)

WHAT WE OFFER:
The postdoctorate will join the RECOVER research unit of INRAE Aix-Marseille University, an active research team composed of more than 75 permanent staff and about 40 non-permanent scholars. The lab is located in the sunny city of Le Tholonet, few kilometers from Aix-en-Provence and close to Marseille. This project takes place among the KiWiPoM project which aims at characterizing transport processes and flow kinematic in porous media, to decipher the role of heterogeneities over the flow transport properties. The research activities will thus be performed in parallel with a PhD thesis which started on October 2023 focusing on flow characterization in 3D model porous media made of random polydisperse beads. This fruitful and collaborative environment will allow for sharing experimental techniques and developing exciting research with complementary approaches, in particular regarding flow visualization in the transparent 3D print/molded porous media, which will be performed adapting a dedicated experimental setup developed for the ongoing PhD thesis.

The gross salary is expected to be around 3100 – 3550 euros/month, depending on past experience. The post-doctorate will also benefit from a good quality of life, enriching interactions in an international environment, with a working site in an outstanding natural setting and a quality company restaurant.

Additional information: The Euraxess Center of Aix-Marseille Université informs foreign visiting professors, researchers, postdoc and PhD candidates about the administrative steps to be undertaken prior to arrival at AMU and the various practical formalities to be completed once in France: visas and entry requirements, insurance, help finding accommodation, support in opening a bank account, etc. More information on AMU EURAXESS Portal 

QUALIFICATIONS, REQUIRED RESEARCH FIELDS, REQUIRED EDUCATION LEVEL, PROFESSIONAL SKILLS, OTHER RESEARCH REQUIREMENTS 
We are looking for a candidate with strong taste for experiments, a potent inclination for experimental curiosity and interest in 3D printing and molding techniques, and/or direct flow visualization. Past experience in laboratory work including flow visualization techniques (PIV/PTV), 3D printing, molding (PDMS/PMMA), or X-ray tomography will be profitable. The candidate is expected to have preferentially a background in fluid mechanics. Backgrounds in additive manufacturing or in geotechnical engineering will also be considered. The post doctorate will be involved at all stages of the project: elaboration of 3D printing technique, sacrificial molding, direct flow visualization, numerical image analysis for flow characterization (PIV, PTV, 3D flow reconstruction).

Soft skills:  Inclination for experiments, Autonomy, faculty for working independently and in a team, willingness to improve and explore new experimental techniques, constructive criticism, curiosity, perseverance and scientific rigor.

A good level in English would be appreciated.

REQUESTED DOCUMENTS OF APPLICATION, ELIGIBILITY CRITERIA, SELECTION PROCESS
Inquiries and applications (including a CV, a résumé of the PhD thesis and of past research experiences) can be sent by email to mathieu.souzy@inrae.fr

HOW TO APPLY: mathieu.souzy@inrae.fr