(PhD) Robust and accurate yield stress fluid flow with the extreme mesh deformation approach (X-MESH)

Offer Description

General Context of the Research

This job offer is related to an ERC Synergy grant titled X-MESH (grant number 101071255) that started on the first of September 2023. The two PIs of this grant are Jean-François Remacle (UCLouvain) and Nicolas Moës (joining UCLouvain  in  July 2024).

The project will develop an innovative approach, X-MESH, to overcome a major difficulty associated with engineering analysis: we aim to provide a revolutionary way to track physical interfaces in finite element simulations using extreme deformation of the meshes. Unprecedented low computational cost, high robustness and accuracy are expected as the proposed approach is designed to avoid the pitfalls of the current methods, especially for topological changes.  The key idea of the project has emerged in a synergistic brainstorming between J.-F. Remacle (meshing methods) and N. Moës (computational methods). This key idea is to allow elements to deform up to zero measure. For example, a triangle can deform to an edge or even a point. This idea is rather extreme and totally revisits the interaction between the meshing community and the computational community who, for decades, have striven to interact through beautiful meshes.

Six areas in fluid and solid mechanics as well as heat transfer are targeted. Interfaces will be either (i) material, i.e. attached to particles of matter (the interface between two immiscible fluids or the dry interface in a wetting and drying model) (ii) immaterial, i.e. migrating through the material (a solidification front, contact front, yield front in yield stress fluid flow or a crack front).

Successes brought by X-MESH are expected in the following engineering areas: safety design and maintenance, manufacturing processes, coastal engineering, energy efficiency, ocean modeling to cite a few. The project takes place in a stimulating environment mixing senior staff  with PhDs and Post-docs to produce and disseminate publications with open source pieces of software. It also intends to create a synergy at large with the computational communities dealing with interfaces and fronts in all fields of science: topology optimization,  superconductivity, tissue growth, hydrogel swelling, crystal growth, ferroelectric crystal etc.

Robust and accurate yield stress fluid flow with the extreme mesh deformation approach (X-MESH).

Some fluids as mayonnaise, mud or toothpaste are non-Newtonian in the sense that the shear stress is not proportional to the rate of shear strain. The shear strain rate is in fact zero below some level of shear stress, called yield stress, and then becomes affine with respect to the shear stress. The flow of a yield stress fluid thus involves rigid zones and shearing zones. A fundamental challenge in the finite element simulation is to capture the front between these two regions, called yield front.

The goal of the thesis is to develop algorithms to capture exactly the yield front with the mesh and apply the proper constitutive model on each side of the front.

This should improve dramatically the solution quality as well as the solver robustness. Knowing to precise location of the rigid solution may even offer the possibility to include some elasticity in this zone. This is vital for some applications.

The thesis will be co-supervised by Prof. Moes and Prof. Remacle, who are the 2 PI's of the X-MESH project.

Requirements

Research Field Engineering » Mechanical engineering

Education Level Master Degree or equivalent

Research Field Engineering » Computer engineering

Education Level Master Degree or equivalent

Research Field Mathematics » Applied mathematics

Education Level Master Degree or equivalent

Skills/Qualifications

The candidate must have obtained a Master's degree in engineering, preferably with a specialization in numerical modeling in solid mechanics. Programming skills (C++, Python) are highly desirable. Knowledge of technical English is essential.

Languages ENGLISH

Level Excellent

Additional Information

Benefits

The Université catholique de Louvain offers attractive thesis salaries (~2400 Euros after taxes) and reimbursement of travel expenses to and from work (public transport).

The research work will be carried out within the framework of an ERC Synergy in a team of around 20 researchers and in an excellent research environment.

A thesis in Belgium takes 4 years to complete.

The town of Louvain la Neuve is a new, pedestrianized and very dynamic city. Brussels is about 20 kilometers away, with a direct train connection to Louvain-la-Neuve.

Selection process

The selection process will be a "rolling" one: candidates who meet the requirements (skills and qualifications) will be interviewed, preferably face-to-face, and a rapid response will be given as to whether or not to commit.  We would like the Ph.D. student to begin his or her research work in 2024, typically in September.

Additional comments

If several excellent candidates apply to this job offer, it's possible that more than one thesis will be funded.

Website for additional job details
http://x-mesh.eu
http://www.gmsh.info

Work Location(s)

Number of offers available 1

Company/Institute Université catholique de Louvain

Country Belgium

City Louvain-la-Neuve

Postal Code 1348

Where to apply

E-mail jean-francois.remacle@uclouvain.be

Contact

City Louvain la Neuve

Website https://uclouvain.be/fr/index.html

Street Place du Levant 1