“Space-Time Discretization of Elasto-Acoustic Wave Equation in Polynomial Trefftz-DG Bases” Discontinuous Finite Element Methods (DG FEM) have proven flexibility and accuracy for solving wave problems in complex media. However, they require a large number of degrees of freedom, which increases the corresponding computational cost compared with that of continuous finite…
“Contribution to the Numerical Reconstruction in Inverse Elasto-Acoustic Scattering” The characterization of hidden objects from scattered wave measurements arises in many applications such as geophysical exploration, non destructive testing, medical imaging, etc. It can be achieved numerically by solving an Inverse Problem. However, this is a nonlinear and ill-posed problem,…
“On the study and development of high-order time integration schemes for ODEs applied to acoustic and electromagnetic wave propagation problems.” In this thesis, we study and develop different families of time integration schemes for linear ODEs. After presenting the space discretisation methods and a review of classical Runge-Kutta schemes in…
“Contributions to Seismic Full Waveform Inversion for Time Harmonic Wave Equations: Stability Estimates, Convergence Analysis, Numerical Experiments involving Large Scale Optimization Algorithms” In this project, we investigate the recovery of subsurface Earth parameters. We consider the seismic imaging as a large scale iterative minimization problem, and deploy the Full…
“Goal-oriented adaptivity using unconventional error representations” In Goal-Oriented Adaptivity (GOA), the error in a Quantity of Interest (QoI) is represented using global error functions of the direct and adjoint problems. This error representation is subsequently bounded above by element-wise error indicators that are used to drive optimal refinements. In…
“Méthodes de réduction de modèles pour l’inversion rapide de mesures de résistivité en forage” Les mesures de résistivité en forage sont communément utilisées pour obtenir une meilleure caractérisation du sous-sol. L’utilisation d’un tube métallique pour cou- vrir le puits complique énormément les simulations numériques pour le potentiel électrique à…
Modélisation et simulation Avancée de phénomènes de propagation d’ondes dans des milieux GéophysIQUEs 3D Mes thèmes de recherche concernent la modélisation et la simulation numérique de la propagation d’ondes géophysiques. Ils ont pour objectif d’améliorer la précision des méthodes d’imagerie sismique (Reverse Time Migration, Full Waveform Inversion) tout en diminuant…
hp-Adaptive Simulation and Inversion of the Magnetotelluric Measurements The magnetotelluric (MT) method is a passive exploration technique that aims at estimating the resistivity distribution of the Earth’s subsurface, and therefore at providing an image of it. This process is divided into two different steps. The first one consists in recording…
“Simulation of elastic wave propagation in time harmonic domain using discontinuous Galerkin methods” The scientific context of this thesis is seismic imaging which aims at recovering the structure of the earth. As the drilling is expensive, the petroleum industry is interested by methods able to reconstruct images of the…
Publications HAL de luquel du labo/EPI magique-3d
