Vincent Legat
Recent publications

is Full Professor of Applied Mathematics and Mechanics in the Ecole Polytechnique de Louvain. His research topics include the development of mathematical models and numerical tools for predicting the behaviour of complex materials and analysing their forming processes., computational rheology, fluid mechanics, modeling of polymeric solutions and melts, modeling of turbulent flows, computational geometry and design, numerical software engineering, non-linear finite element methods and formulations, error estimation and adaptive numerical methods, parallel computing.

IMMC main research direction(s):
Computational science
Civil and environmental engineering
Fluid mechanics

finite elements
fluvial hydraulics
geophysical and environmental fluid dynamics
granular materials
non-equilibrium thermodynamics
reacting flows
two-phase flows

Research group(s): MEMA

PhD and Post-doc researchers under my supervision:

Modelling and diagnosing transport processes in a tropical river-lake-delta-sea continuum Application to the Mahakam River (Borneo Island, Indonesia)
Insaf Draoui

The project aims to model and diagnose transport processes in the Mahakam delta using a coupled 1D-2D model. The model will be based on SLIM. Advanced diagnostic methods will be inspired by CART and pertain to both water and sediment. In addition, an attempt will be made to apply the newly-introduced concept of partial age to sediment.

Development of the 3D model of SLIM
Ange Ishimwe

SLIM is a simulation software which resolves the hydrodynamical equation with the use of finite elemnts. My goal is to developpe and improve the 3D model of SLIM. The two criteria are the precision of the results and the computation speed.

Modèle hybride multi- échelle pour l’ étude rh éologique des solutions de macromolécules
Nathan Coppin

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.

SLIM-G : GPU-accelerated SLIM
Miguel De Le Court

I am developing a GPU version of the SLIM ocean model in order to significantly increase its performance, which unlocks previously unreachable resolutions.

Most current ocean models still use the CPU for all the computations, which makes them terribly slow, and unable to use the next generation of supercomputers such as LUMI. Among the ocean models that are accelerated on the GPU, all of them either use finite differences, which lacks flexibility in the meshes, or finite volumes, which are often low order methods. Contrary to that, SLIM uses the discontinuous Galerkin Finite elements method, which is known for its low diffusivity in advective processes and maps very well to the massively parallel architecture of the GPU.

The current GPU version is fully working in 2D and it absolutely destroys the CPU version, showing a speedups of 50–130x. (R9 5900X vs RTX2080 vs A100). See the attached figure to get an idea of the damage.

Recent publications

See complete list of publications

Journal Articles

1. Coppin, Nathan; Constant, Matthieu; Lambrechts, Jonathan; Dubois, Frédéric; Legat, Vincent. Numerical analysis of the drag on a rigid body in an immersed granular flow. In: Computational Particle Mechanics, Vol. 9, p. 393-406 (2022). doi:10.1007/s40571-021-00418-w.

2. Beuken, Loïc; Cheffert, Olivier; Tutueva, Aleksandra; Butusov, Denis; Legat, Vincent. Numerical Stability and Performance of Semi-Explicit and Semi-Implicit Predictor–Corrector Methods. In: Mathematics, Vol. 10, no.12, p. 2015 (2022). doi:10.3390/math10122015.

3. Fedoseev, Petre; Karimov, Artur; Legat, Vincent; Butusov, Denis. Preference and Stability Regions for Semi-Implicit Composition Schemes. In: Mathematics, Vol. 10(22), no. 10.3390/math10224327 , p. 4327 (2022). doi:10.3390/math10224327.

4. Constant, Matthieu; Coppin, Nathan; Dubois, Frédéric; Artoni, Riccardo; Lambrechts, Jonathan; Legat, Vincent. Numerical investigation of the density sorting of grains using water jigging. In: Powder Technology, Vol. 393, no.1, p. 705-721 (2021). doi:10.1016/j.powtec.2021.07.036.

5. Constant, Matthieu; Coppin, Nathan; Dubois, Frédéric; Vidal, Valérie; Legat, Vincent; Lambrechts, Jonathan. Simulation of air invasion in immersed granular beds with an unresolved FEM–DEM model. In: Computational Particle Mechanics, Vol. 8, p. 535-560 (2021). doi:10.1007/s40571-020-00351-4.

6. Deleersnijder, Eric; Draoui, Insaf; Lambrechts, Jonathan; Legat, Vincent; Mouchet Anne. Consistent boundary conditions for age calculations. In: Water, Vol. 12, p. 1274 (2020). doi:10.3390/w12051274.

7. Van Achter, Guillian; Ponsoni, Leandro; Massonnet, François; Fichefet, Thierry; Legat, Vincent. Brief communication: Arctic sea ice thickness internal variability and its changes under historical and anthropogenic forcing. In: The Cryosphere, Vol. 14, no.10, p. 3479-3486 (2020). doi:10.5194/tc-14-3479-2020.

8. Constant, Matthieu; Dubois, Frédéric; Lambrechts, Jonathan; Legat, Vincent. Implementation of an unresolved stabilised FEM-DEM model to solve immersed granular flows. In: Computational Particle Mechanics, Vol. 6, no. 2, p. 213-226 (01/04/2019). doi:10.1007/s40571-018-0209-4.

9. Delandmeter, Philippe; Lambrechts, Jonathan; Legat, Vincent; Vallaeys, Valentin; Naithani, Jaya; Thiery, Wim; Remacle, Jean-François; Deleersnijder, Eric. A fully consistent and conservative vertically adaptive coordinate system for SLIM 3D v0.4 with an application to the thermocline oscillations of Lake Tanganyika. In: Geoscientific Model Development, Vol. 11, no.3, p. 1161-1179 (2018). doi:10.5194/gmd-11-1161-2018.

10. Delandmeter, Philippe; Lambrechts, Jonathan; Marmorino, George O.; Legat, Vincent; Wolanski, Eric; Remacle, Jean-Fran?ois; Chen, Wei; Deleersnijder, Eric. Submesoscale tidal eddies in the wake of coral islands and reefs: satellite data and numerical modelling. In: Ocean Dynamics : theoretical, computational oceanography and monitoring, Vol. 67, no.7, p. 897-913 (2017). doi:10.1007/s10236-017-1066-z.

Conference Papers

1. Draoui, Insaf; Lambrechts, Jonathan; Legat, Vincent; Deleersnijder, Eric. The discontinuous Galerkin method for coupling a 1D river model to a 2D shallow water one. 2022 xxx. doi:10.5194/egusphere-egu22-1084.

2. Ishimwe, Ange Pacifique; Lambrechts, Jonathan; Legat, Vincent; Deleersnijder, Eric. A split-explicit Runge-Kutta method for 3D hydrodynamic equations for coastal applications. 2022 xxx. doi:10.5194/egusphere-egu22-2452.

3. Draoui, Insaf; Lambrechts, Jonathan; Legat, Vincent; Soares Frazao, Sandra; Hoitink Ton; Deleersnijder, Eric. Discontinuous Galerkin method for 1D shallow water models. 2021 xxx.

4. Draoui, Insaf; Lambrechts, Jonathan; Legat, Vincent; Soares Frazao, Sandra; Hoitink, Ton (A.J.F.); Deleersnijder, Eric. Discontinuous Galerkin method for 1D river flows. In: River Flow 2020, Taylor & Francis Group: London, 2020, 978-0-367-62773-7, p. 1-8 xxx.

5. Coppin, Nathan; Constant, Matthieu; Legat, Vincent; Lambrechts, Jonathan; Dubois, Frédéric. Validation du frottement dans un modèle multi-échelles d'écoulements granulaires immergés en vue de l'étude numérique de la traînée. 2019 xxx.

6. Constant, Matthieu; Artoni, Riccardo; Dubois, Frédéric; Lambrechts, Jonathan; Legat, Vincent. Sorting grains by successive depositions computed using an unresolved FEM-DEM multiscale model. 2019 xxx.

7. Constant, Matthieu; Vidal, Valérie; Dubois, Frédéric; Lambrechts, Jonathan; Legat, Vincent. Approche multi-échelles pour simuler l'injection d'air au sein de matrices granulaires immergées. 2019 xxx.

8. Deleersnijder, Eric; Dobbelaere, Thomas; Draoui, Insaf; Hanert, Emmanuel; Anh Le Hoang; Ishimwe, Ange; Lambrechts, Jonathan; Legat, Vincent; Saint-Amand, Antoine; Soares Frazao, Sandra; Vallaeys, Valentin; Vincent, David. SLIM: A multi-scale model of the land-sea continuum. 2019 xxx.

9. Legat, Vincent; Constant, Matthieu; Lambrechts, Jonathan; Frédéric Dubois. A New FEM/DEM Multiscale Model to Solve Immersed Granular Flows Based on Suspension Drops Simulations. 2018 xxx.

10. MATA Pablo; Delandmeter, Philippe; Lambrechts, Jonathan; Deleersnijder, Eric; Legat, Vincent. Numerical study of the hydrodynamics of a marine water body in Western Patagonia. 2018 xxx.

Book Chapters

1. Gourgue, Olivier; Deleersnijder, Eric; Legat, Vincent; Marchal, Emmanuel; White, Laurent. Free and forced thermocline oscillations in Lake Tanganyika. In: The Factor Separation Method in the Atmosphere: Applications and Future Prospects , xxx, 2011. 978-0-521-19173-9. xxx xxx. doi:10.1017/CBO9780511921414.011.


1. Legat, Vincent. Méthodes d'éléments finis pour le calcul d'écoulements tridimensionnels à surfaces libres, prom. : Marchal, J. M. ; Crochet, Marcel J., 1992.