BMS workshop

Contribution List

9. Annika Lang - Computing solutions to stochastic partial differential equations on surfaces

22/05/2024, 14:00

Looking around us, many surfaces including the Earth are no plain Euclidean domains but special cases of Riemannian manifolds. One way of describing uncertain physical phenomena on these surfaces is via stochastic partial differential equations. In this talk, I will introduce how to compute approximations of solutions to such equations and give convergence results to characterize the quality...

10. Christophe Berthon - Artificial numerical viscosity to get discrete entropy inequalities

22/05/2024, 14:45

When considering the numerical approximation of weak solutions of systems of conservation laws, the satisfaction of discrete entropy inequalities is, in general, very difficult to be obtained. In the present talk, we present a suitable control of the artificial numerical viscosity in order to recover the expected discrete entropy inequalities. Moreover, the artificial viscosity control turns...

11. Mireille Bossy - Long-range correlation modeling for Lagrangian transport in turbulence and application to reduced wind gust model

22/05/2024, 16:00

The ability to model, simulate, and predict dispersed turbulent two-phase flows is crucial for various industrial and environmental applications. In this context, the development of stochastic Lagrangian models for particle phase tracking is closely linked with the development of reduced PDE models, such as URANS or LES methods used in various applications. These models, which neglect small...

12. Philippe Helluy - High order entropy dissipative lattice-Boltzmann method

22/05/2024, 16:45

The Lattice-Boltzmann Method (LBM) is a highly efficient technique for simulating fluid flows. It is traditionally reserved to low-Mach viscous flows. In this talk we show how to extend it to compressible flows, thanks to the vectorial kinetic approach of Bouchut, how to achieve high-order accuracy with entropy dissipation and how to handle boundary conditions.

5. Analysis seminar - Daniel Han-Kwan

23/05/2024, 10:00

1. David Gérard-Varet - Analyse mathématique des couches limites

23/05/2024, 14:00

Nous tenterons dans cet exposé de faire une synthèse de résultats mathématiques obtenus ces dernières années autour du phénomène de couche limite en hydrodynamique.

4. Frédéric Lagoutière - Convergence of a semi-discrete mesoscopic multi-fluid model toward the Baer-Nunziato equations

23/05/2024, 14:45

We consider a bi-fluid Navier-Stokes semi-discrete model with two fluids with different pressure laws, at a scale where they are unmixed. We let this scale converge to 0 and we prove that the solution converges to the solution to the continuous Baer-Nunziato model in which all the coefficients are known (including the relaxation coefficient). The interest of this semi-dicrete approach is that...

3. Urbain Vaes - Derivative-free Bayesian Inversion Using Multiscale Dynamics

23/05/2024, 16:00

Inverse problems are ubiquitous because they formalize the integration of data with mathematical models. In many scientific applications the forward model is expensive to evaluate, and adjoint computations are difficult to employ; in this setting derivative-free methods which involve a small number of forward model evaluations are an attractive proposition. Ensemble Kalman based interacting...

2. Giacomo Dimarco - Control and uncertainty quantification through deep neural networks for plasma simulation

23/05/2024, 16:45

We will consider the development of numerical methods for simulating plasmas in magnetic confinement nuclear fusion reactors. In particular, we focus on the Vlasov-Maxwell equations describing out of equilibrium plasmas influenced by an external magnetic field and we approximate this model through the use of particle methods. We will additionally set an optimal control problem aiming at...

6. Nina Aguillon - Barotropic/baroclinic splitting in ocean models

24/05/2024, 10:00

This numerical strategy is commonly used in the ocean model community to reduce the computationnal cost. This model are 3 dimensional and frequently run with over 40 layers along the vertical. In a monolothic code the timestep is constrained by the speed of the gravity waves. In the barotropic/baroclinic splitting, the surface waves and the mean horizontal velocities are treated in a 2D...

7. Georg Maierhofer - Structure-preserving low-regularity integrators for dispersive nonlinear equations

24/05/2024, 11:00

Dispersive nonlinear partial differential equations can be used to describe a range of physical systems, from water waves to spin states in ferromagnetism. The numerical approximation of solutions with limited differentiability (low regularity) is crucial for simulating fascinating phenomena arising in these systems including emerging structures in random wave fields and dynamics of domain...

8. Pauline Lafitte - Towards a scheme of uniform order in time for the Fokker-Planck equation

24/05/2024, 11:45

The sensitive issue of the discretisation of Neumann's boundary condition for a Fokker-Planck equation while preserving self-adjointness led us to the study of an inconsistent scheme for the evolutionary or stationary heat equation. Together with Guillaume Dujardin, we showed the uniform convergence in time at order 1/2 for this last scheme, under a classical stability condition, and pursue...