Ongoing research projects
Ongoing research projects in iMMC (March 2023)
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:
List of projects related to: Computational science
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.
|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.
|Efficient and scalable frameworks for PDE simulations|
Researcher: Thomas Gillis
Supervisor(s): Philippe Chatelain
focuses his research on the development of efficient and scalable computational framework for the simulation of 3D PDEs on massively parallel and heterogeneous architectures.
|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.
|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 UCLouvain. This bio-mechanical model will be coupled to an aerodynamical model based on a vortex particle-mesh code (VPM) developed at UCLouvain as well.
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.
|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 UCLouvain, 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.
|AI-based control policies towards efficient collective behaviours of flow agents and their application to fish schooling|
Researcher: Denis Dumoulin
Supervisor(s): Philippe Chatelain
The principal objective is to shed light on mechanisms allowing anguiliform swimmers to swim very efficiently either on their own or in group.
Simulations rely on an unsteady panel method with vortex shedding and on reinforcement learning.
|2-phase CFD simulations of electrolyte-bubble interactions during alkaline water electrolysis|
Researcher: Kevin Van Droogenbroek
Supervisor(s): Joris Proost
In today’s world, concern is growing about the future of energy. Despite very ambitious international climate goals by 2050, global energy-related carbon dioxide (CO2) emissions keep increasing. In order to tackle this problem, hydrogen (H2) seems to be the right solution since it is a way to produce, store, move and use energy in a clean way. However, 95% of the actual hydrogen production is made of grey hydrogen, e.g. H2 produced from fossil energies, which leads to high CO2 emissions in the atmosphere. One way to decarbonise this energy vector is to produce green hydrogen by means of renewable energies (solar panels, wind turbines, etc). This is where my research project funded by the Walloon region comes in, focusing on the production of green hydrogen by alkaline water electrolysis (AWE).
In general, AWE is characterised by the use of two planar electrodes separated by a certain distance and operating in a liquid alkaline electrolyte solution (e.g. KOH, potassium hydroxide). However, the efficiency of the process can be improved by the use of 3D electrodes in a zero-gap cell configuration. This configuration is the one that will be used in the scope of this research and it is depicted in Figure 1. The chemical reactions taking place at the cathode and at the anode are also highlighted.
More specifically, the work will consist in the fluid mechanical modeling of liquid and gaseous flows within alkaline electrolysis cells filled with 3D porous structures. The study of liquid electrolyte flow and of gaseous hydrogen bubble formation and escape will allow to optimise the performance of the electrolyser. Computational Fluid Dynamics (CFD) is a powerful numerical tool that will be used during this project to determine the optimal flow parameters required to homogenise the electrolyte flow (to take advantage of the full specific area provided by the electrodes) while favouring hydrogen bubbles removal from the electrolysis cell (to avoid bubble entrapment within the complex 3D structure).
As an example, the added value of a numerical simulation for a better understanding of the electrolyte flux distribution within an empty cell (e.g. without 3D structure) is shown in Figure 2. The velocity field of the electrolyte (in m/s) was simulated on the OpenFOAM software. Note that the geometry of the cell corresponds to the one of the pilot electrolyser used at UCLouvain (see Figure 3).