30-month Postdoc position in Fluid mechanics: Flow kinematics in transparent replicas of geomat[...]

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): Physics, Geosciences

MAIN SUB RESEARCH FIELD OR DISCIPLINES: Fluid mechanics

JOB / OFFER DESCRIPTION:
The research unit RECOVER from INRAE invites 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 innovative 3D printing and molding techniques. Achieving such transparent replicas will allow for investigation of transport processes in complex 3D porous microstructures. This postdoctoral position is fully funded by the ANR-23-CE51-0024 JCJC KiWiPoM.

Geomaterials are complex porous materials presenting a wide diversity of structures that set the flow kinematics of any fluids through them. Understanding what drives and controls the transport processes in porous media is crucial for a broad range of applications. Transport processes are characterized by investigating the flow velocity fields, usually performed using direct flow visualization techniques such as particle image velocimetry (PIV) or particle tracking velocimetry (PTV). Due to the opaque nature of porous media, direct flow visualization is typically prohibited within real soil microstructures, making flow kinematic characterization particularly challenging in 3D porous media. This project aims to tackle this experimental limitation by developing innovative 3D printing & molding techniques to replicate the microstructure of real porous materials and geomaterial samples scanned via X-ray tomography.

The 3D printing & molding techniques will involve sacrificial 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 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 approaches to geomechanics will unlock the challenging issue of opacity prohibiting direct visualizations in the porous media community and allow for high control of the investigated microstructure, optimizing transport processes through porous media by determining how local alterations of a microstructure may enhance transport processes. This promising approach requires rigorous tuning, as the technical feasibility depends on the 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 direct flow visualization. The flow will then be characterized by reconstructing the 3D velocity field using successive scans of the flow velocity.

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

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, a few kilometers from Aix-en-Provence and close to Marseille. This project takes place within the KiWiPoM project, which aims to characterize transport processes and flow kinematics in porous media, deciphering the role of heterogeneities over the flow transport properties. Research activities will be performed in parallel with a PhD thesis focusing on flow characterization in 3D model porous media made of random polydisperse beads. This collaborative environment will allow for sharing experimental techniques and developing exciting research with complementary approaches, particularly regarding flow visualization in the transparent 3D printed/molded porous media, 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.

QUALIFICATIONS, REQUIRED RESEARCH FIELDS, REQUIRED EDUCATION LEVEL, PROFESSIONAL SKILLS, OTHER RESEARCH REQUIREMENTS:
We are looking for a candidate with a strong interest in experiments, 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 beneficial. The candidate is expected to have a background in fluid mechanics, with backgrounds in additive manufacturing or geotechnical engineering also considered. The postdoctorate will be involved at all stages of the project: elaboration of 3D printing techniques, sacrificial molding, direct flow visualization, and numerical image analysis for flow characterization (PIV, PTV, 3D flow reconstruction).

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

A good level of English is appreciated.

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