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  • EDP

    Jeudi 1er juin 2017 14:00-15:45 - Thibaud Beltzung, Hélène Mertz et Maxime Stauffert - Laboratoire de Mathématiques de Versailles

    T. Beltzung, H. Mertz et M. Stauffert : Présentations de leurs travaux par les 3 doctorants en deuxième année de l’équipe

    Résumé :
    Exposé de Thibaud Beltzung
    Titre : Simulation and modelisation of fluid-structure interactions in two-phase flows.
    Résumé : In the context of fluid-structure interaction in steam generator of pressurized water reactors, we aim to develop a full eulerian formulation of a multiphase solver. The aim of this work is to model and compute two-phase interfaces on simplified industrial configurations in order to develop a better understanding of the underlying fluid-structure interactions. Our interest focuses on numerical methods for High-Performance Computing (HPC). For immersed solids, we interest ourselves to (non-body conformal) cartesian grid methods. For the liquid/gas interfaces, flux limiting schemes for transport equations is investigated. Numerical diffusion is, for some of them, bounded over time. We will then interest ourselves to the numerical implementation of surface tension for the velocity-pressure equations in the scope of incompressible flows.
    Exposé de Hélène Mertz
    Titre : Implementation of chemical models in a DSMC Code.
    Résumé : DSMC methods are used by Airbus Safran Launchers since the 80’s in order to simulate hypersonic rarefied flows. This method can be used to compute aerodynamic force and moments on a spacecraft. In order to have a more accurate idea of the fluxes in the context of reentry, a chemistry model need to be implemented in the DSMC code. Indeed, the energy used for the chemical reactions can have an impact on the fluxes. The main principles of the DSMC method will firstly be presented. The distribution of internal energy between rotational and vibrational energy has been implemented and validated. Two different chemical models have been implemented, studied, and will be compared throw the first results obtained by the in-house DSMC code regarding the industrial need of Airbus Safran Launchers.
    Exposé de Maxime Stauffert
    Titre : On all-regime, high-order and well-balanced Lagrange-Projection type schemes for the shallow water equations.
    Résumé : The purpose of this work is to design a high order scheme for the Shallow Water Equations (SWE) thanks to a Lagrange-Projection type approach.
    We propose to extend the recent implicit-explicit schemes developed in the framework of compressible single or two-phase flows. These methods enjoy several good features : they provide an accurate approximation independently of the Mach regime. They also enable the use of time steps that are no longer constrained by the sound velocity thanks to an implicit treatment of the acoustic waves and an explicit treatment of the material waves.
    We have for now studied two different extensions of the schemes : one towards the SWE in the Finite-Volume framework, and one towards the Discontinuous Galerkin (DG) discretization for the barotropic Euler equations. In the present case, we propose a combination of both, that is to say a Lagrange-Projection type DG scheme for the SWE system. We particularly focus on the discretization of the non-conservative terms, and more specifically on the well-balanced property of the method, which is not trivial for high order schemes.

    Lieu : Salle G210, bât. Germain.

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  • jeunes

    Jeudi 1er juin 2017 15:15-16:15 - Pierrick Méaux et Romain Gay - École Normale Supérieure


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