Ongoing research projects

IMMC

Ongoing research projects in iMMC (November 2021)


This a short description of research projects which are presently under progress in iMMC.
Hereunder, you may select one research direction or choose to apply another filter:

Biomedical engineering

Computational science

Civil and environmental engineering

Dynamical and electromechanical systems

Energy

Fluid mechanics

Processing and characterisation of materials

Chemical engineering

Solid mechanics


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List of projects related to: Computational science




WholeTrack
Researcher: Nicolas Docquier
Supervisor(s): Paul Fisette

The project aims at improving railway track lifecycle by improving its components such as the ballast, the sleeper, elastic pads, ... It consists in developing computer models coupling multi-body system dynamics (MBS) and granular modelling method (the discrete element method, DEM). Full scale experiments are conducted in parallel to validate the numerical models and assess the developed solutions.



Development of high-toughness cryogenic alloys
Researcher: Alvise Miotti Bettanini
Supervisor(s): Pascal Jacques

Materials that can perform at extremely low temperatures are in great demand. Applications span from tanks and pressure vessels for LNG (Liquefied Natural Gas) carriers to structural materials in extreme conditions, like the upcoming exploration of Mars. In this context, it is critical to ensure very high toughness, which measures the resistance to crack propagation, at cryogenic temperatures. In this project, the experimental development of Fe-based superalloys is guided by a CALPHAD-based methodology, which allows the calculation of phase stability and phase transformation with computational models in order to reduce the experimental effort and hasten the development cycle of new materials.



Implementation of an incompressible hybrid Eulerian-Lagrangian external flow solver
Researcher: Philippe Billuart
Supervisor(s): Grégoire Winckelmans, Philippe Chatelain

Philippe Billuart is working on the development of a new numerical solver that will be able to solve accurately and efficiently any low Mach number external flows. His research is focusing on the hybrid Eulerian-Lagrangian solvers for the incompressible Navier-Stokes equations. Those approaches are based on the decomposition of the computational domain : an Eulerian grid-based solver is used for the computation of the near-wall region, while a Lagrangian vortex method solves the wake region. Even though the coupling of particle methods with Eulerian solvers is not new, only 3D weak coupling were developed so far. This thesis aims to develop a 3D strong coupling ; i.e. a coupling where the Schwarz iterations are not longer required to ensure consistent boundary conditions on each subdomain. As the Schwarz algorithm becomes expensive in 3D, the computational gain in the developed approach should be very significant.



Crane dynamis (CRAMIC)
Researcher: Olivier Lantsoght
Supervisor(s): Paul Fisette

Historically, the cranes of the ports were assumed to be static or cyclical but, because of the increases in speed and loads, they are becoming more and more dynamic. As a result, load on the rail tracks is increasing and negative effects occurs (such as uncontrolled motion, track deformation…). As one of the partners of CRAMIC global project, through multibody and granular analysis of the system crane-railway.
On one side, we focus on identifying and studying the present dynamic effects, participating in developing new track technologies and helping monitoring cranes to organize a future maintenance. On the other side, we focus on the interaction between sleepers and ballast, participating in creating new sleeper geometries.



Modeling and simulation of water electrolysis.
Researcher: Christos Georgiadis
Supervisor(s): Joris Proost

The main objective of our work is to develop models for the simulation of 2-phase flows through electrodes. After the initial validation of the model, we will perform a detailed analysis of the flow and electrochemical properties of the system, in conjunction with experimental data. The final objective will be the design of optimal electrode geometries for water electrolysis.



Curvilinear mesh adaptation
Researcher: Amaury Johnen
Supervisor(s): Jean-François Remacle

graduated as a physician engineer at the University of Liège (Belgium) in 2011. Then he accomplished a PhD in the topic of quadrangular mesh generation and cuvilinear mesh validation, under the supervision of professor Christophe Geuzaine. He started a postdoctoral research in January 2016 under the supervision of professor Jean-François Remacle for working on curvilinear mesh generation, hex-dominant mesh generation and mesh validation.



All-hexahedral meshing
Researcher: Kilian Verhetsel
Supervisor(s): Jean-François Remacle

While there exist algorithms to generate hex-dominant meshes, which contain a majority of hexahedra as well as a mixture of tetrahedra, prisms, and pyramids, automatically generating hexahedral meshes with elements of a reasonable quality is not currently possible. Subdividing the elements of a hex-dominant mesh could allow hexahedral meshes to be generated automatically, but the best known subdivision of a pyramid requires too many elements to be practical (see figure).

My work focuses on finding all-hexahedral meshes of small models such as this pyramid by first finding a topological solution using combinatorial search techniques. A geometric mesh will then be produced by finding coordinates for each vertex in the mesh.



Hextreme
Researcher: François Henrotte
Supervisor(s): Jean-François Remacle

completed his Engineering Degree in 1991 and his PhD in 2000, both at the University of Liège in Belgium. He then spent 4 years at the Katholieke Universiteit Leuven and 6 years at the Institut für Elektrische Maschinen in Aachen, Germany, and is now with the UCL and the ULiège. Developer in the open-source packages Gmsh, GetDP and Onelab, he has also developed skills in the multiphysics simulation of electrical machines and drives. His main interests are finite element analysis, numerical modeling, electromechanical coupling, material properties (hysteresis, iron losses, superconductors), applied mathematics (differential geometry, algebraic topology, convex analysis, dual analysis, energy methods), multiscale methods, sensitivity and optimization.



Poly-cube decomposition of 3D volumes
Researcher: Jovana Jezdimirovic
Supervisor(s): Jean-François Remacle

The aim of the research thesis is to push forward the state-of-the-art of mesh generation and propose for the first time a methodology that allows to automatically create structured multi-block meshes for general 3D domains. For that, an innovative approach that enables automatic decomposition of a general 3D domain into “poly-cubes” is proposed. A “poly-cube” map is a mechanism that allows a seamless parameterization of a 3D domain. The “poly-cube” decomposition provides the multi-block structure that is needed for structured meshing. In order to achieve this goal, the first part of the thesis is dedicated to the development of a “poly-quad” decomposition of a general 2D surface. It is relied on solving adequate Ginzburg Landau equations in order to develop a robust procedure that generates cross fields and locates critical points. Existence and location of critical points – represented as elliptic Fekete points are proved in recent results by Jezdimirovic, 2017. Further, critical points will be connected through the integral lines leading to an automatic decomposition of the domain into “quadrilaterals”. In the next step, the presented idea will be extended to 3D in order to create automatic algorithm for the “poly-cube” decomposition of 3D volumes.



Modelisation and optimization of bird flight
Researcher: Victor Colognesi
Supervisor(s): Philippe Chatelain, Renaud Ronsse

This research project aims at modeling and optimizing bird flight. The goal of this modelization is to get a deep understanding of the mechanisms that govern avian flight and the best way to understand it is to re-create it. That is, the flight will be modeled starting from the given anatomy of a bird and the kinematics will be the result of an optimization process aiming at the most optimal flight.
Compared to other existing studies on the subject of bird flight, this project will follow a "bottom-up" approach, all the way from muscle activation, up to the wing aerodynamics and gait optimization. This approach is necessary to be able to evaluate key values such as metabolic rates, ...
This will allow us to answer a few questions such as :
- What are the mechanisms enabling high efficiency in bird flight ?
- How do we achieve a stable flapping flight ?
This work is purely numerical. The bio-mechanical model of the bird is developed using the multi-body solver Robotran developed at UCL. This bio-mechanical model will be coupled to an aerodynamical model based on a vortex particle-mesh code (VPM) developed at UCL as well.



DNS of reacting particle flows for mesoscale modeling
Researcher: Baptiste Hardy
Supervisor(s): Juray De Wilde, Grégoire Winckelmans

Gas-solid flows are encountered in many natural and industrial phenomena. Fluidized beds are the most well known application of gas-solid reactors in the chemical industry (catalytic cracking, biomass conversion,...).
However, the simulation of such equipments at large scale is still an issue due to the tracking of billions of particles carrying the reaction while interacting with the gas flow. Eulerian-Eulerian models are currently very popular because they describe the solid phase as a continuum, hence drastically lowering the computational cost. Though, these models require closure relations for momentum, heat and mass transfer, often obtained on empirical bases.
The goal of this research is to extract closure laws from Direct Numerical Simulations at particle scale using the Immersed Boundary Method in order to provide new mesoscale models built on physical grounds.



3D crossfield generation for multibloc decomposition
Researcher: Alexandre Chemin
Supervisor(s): Jean-François Remacle

The aim of the project is to realize multibloc decomposition of 3D volumes in order to generate full hex meshes. Nowadays, this kind of decomposition is done by hand. The purpose of this work is to be able to do it in an automatic way. In order to reach this objective, we are generating 3D crossfields in this volume to locate singular points and automatize the decomposition.



Automatic quadrilateral and hexahedral meshing
Researcher: Maxence Reberol
Supervisor(s): Jean-François Remacle

My research interests are automatic block decomposition, quadrilateral meshing, hexahedral meshing and robust hex-dominant meshing.



Flight Control and Wake Characterization of Migratory Birds
Researcher: Gianmarco Ducci
Supervisor(s): Renaud Ronsse, Philippe Chatelain

The RevealFlight project aims at shedding light on the efficiency optimization mechanisms deployed by biological flyers, with a specific focus on migratory birds. The efficiency-seeking mechanisms will be sought through the numerical reproduction of flight that includes the morphology, the neuro-muscular configuration and the gait generation. This resulting gait then exploits aerodynamics at the scale of an individual (unsteady lift generation) and at the level of the flock (formation flight). This project thus proposes to synthesize the flight mechanics of birds into a unified framework, combining bio-mechanical, sensory, aerodynamic and social interaction models, in order to reproduce the flying gaits and the interactions within a flock.
A neuro-mechanical model of the birds is currently under development, capturing bio-inspired principles both in the wing bio-mechanics (e.g. structure and compliance) and in its coordinated control (through e.g. a network of coordinated oscillators). The dynamics of this model will be solved by means a multi-body solver and in turn, coupled to a massively parallel flow solver (an implementation of the Vortex Particle-Mesh method) in order to capture the bird’s wake up to the scales of the flock. The study of self-organization phenomena and inter-bird interactions are currently beginning on simple conceptual models, and will be gradually extended to more advanced models developed during the project. It will aim at comparing the efficiency of flocks of selfish flyers with that of flocks in which collaboration takes place, whether implicitly or explicitly.
In my global project picture, the following bottom-up strategy will be adopted:
- Wake characterization: This task studies the wake in terms of the vortex dynamics at play over long distances. The candidate will perform simulations of flying agents in long computational domains in order to capture the wake behavior (topology, instabilities and decay) over longer times and larger scales. This will provide another basis of validation of the project results, given the volume of work on bird wakes;
- Flight stabilization in turbulent or wake-impacted flow: This task aims at the realization of a stabilized flight within a perturbed flow. Two perturbations are envisioned: ambient turbulence and an analytical wake composed of two counter-rotating vortices. Il will Combine previously synthesized gaits and control schemes in order to study the stability of the flyer in a turbulent flow or inside a wake;
- Maneuvers: This task realizes the first maneuvers of the virtual flyer: avoidance and trajectory tracking that will be leveraged in the simulation of multiple flyers that need to interact and swap places. In the present task, this trajectory is still prescribed, in a step towards an autonomous decision-making agent. In order to realize maneuvers, this task implements a control layer above the controllers developed in earlier tasks. Complex maneuvers will be achieved by closing the loop between trajectory errors and the inputs of the lower level controller.



Modèle hybride multi- échelle pour l’ étude rh éologique des solutions de macromolécules
Researcher: Nathan Coppin
Supervisor(s): Vincent Legat

graduated in physical engineering at Université Catholique de Louvain in 2018 and is currently pursuing a PhD under the supervision of Prof. Vincent Legat. The goal of his thesis is to study the performance of the MigFlow Software using applications that require the management of frictional contacts.



Development of high-fidelity numerical methods for the simulation of the aerothermal ablation of space debris during atmospheric entry
Researcher: David Henneaux
Supervisor(s): Philippe Chatelain

This project, lead in collabaration with the von Karman Institute (VKI) and Cenaero, aims at developing high-fidelity numerical methods for the simulation of the aerothermal ablation of space debris during an atmospheric entry.

The number of space debris orbiting the Earth is becoming increasingly problematic for the integrity of operational satellites and the future access to space. The many space debris mitigation projects currently under study require an accurate prediction of the degradation of these objects when they re-enter the atmosphere in order to comply with the severe re-entry safety requirements.

Dedicated engineering softwares are used to assess the survivability of these debris. However, the correlation-based models implemented in these software lack accuracy and they do not allow to gain insight into the complex flow phenomena taking place near the surface of the body, yet essential for the conception of new satellites designed for demise. That is why CFD methods are needed to study this complex situation. But the methods currently available rely on simplifying assumptions that compromise the reliability of the results.

The objective of this project is to develop new high-fidelity numerical methods able to deal with the presence of the three phases in the same domain and their complex interactions. They will be grouped into the ARGO code under development at CENAERO, VKI, and UCL, which relies on the discontinuous Galerkin method. To do so, a highly-accurate multiphase method coupled with evaporation and surface tension models and based on a sharp interface approach will be employed for the treatment of the gas-liquid interface, while a state of the art melting method accounting for the diffuse character of the liquid-solid interface will be considered. Both methods will be built to work with multicomponent compressible equations. The code will then be validated with experimental data from the VKI Plasmatron facility.



Detecting and using locomotion affordances for lower-limb prostheses by active vision
Researcher: Ali Hussein Al-Dabbagh
Supervisor(s): Renaud Ronsse

Healthy lower-limb biomechanics reveals that active prostheses are necessary to provide amputees with human-like dynamics in various locomotion tasks like walking or stair ascending/descending. Ali’s project is about the specific challenges associated to the transition between two of these tasks, where the control parameters of the device has to be smoothly and timely adapted. Active vision is proposed to be used to augment the prosthesis with vision-based detection of possible locomotion affordances, therefore anticipating these transitions as a function of the user’s behavior.



FLEXibilize combined cycle power plant through Power-to-X solutions using non-CONventional FUels (FLEXnCONFU)
Researcher: Azd Zayoud
Supervisor(s): Francesco Contino, Hervé Jeanmart

FLEXnCONFU project aims to demonstrate the flexibility of combined cycle power plants, using hydrogen, or an ammonia carrier, as an energy storage elements.

A comprehensive model will be developed to evaluate the contribution of imported synthetic/electro fuels and their usages and the non-energy use of energy vectors. The model will be used in different scenarios considering two objectives: the minimization of the economic cost (LCOE) and the minimization of the Global Warming Potential (GWP). However, when taking the parameters to optimize as perfectly known, the real objective could even be really far, leading to a fragile optimum, and therefore insecurity of supply. Instead of deterministic optimization, this task will include uncertainty quantification analysis in order to perform robust optimization instead. Considering the uncertainties, it will provide much richer information to policy maker or system designers.