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Prof. Gérard Liger-Belair (CNRS)12/12/2016 09:00Bubbles in a glass of champagne may seem like the acme of frivolity to most of people, but in fact they may rather be considered as a fantastic playground for any fluid physicist. In a glass of champagne, about a million bubbles will nucleate and rise if you resist drinking from your flute. The so-called effervescence process, which enlivens champagne and sparkling wines tasting, is the result...Aller à la page de la contribution
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M. Arthur Talpaert (CEA and Ecole Polytechnique (Paris-Saclay))12/12/2016 09:45This talk presents the implementation of the simulation of two-phase flows in conditions of water-cooled nuclear reactors, at the scale of individual bubbles. To achieve that, we study several models for Thermal-Hydraulic flows and we focus on a technique for the capture of the thin interface between liquid and vapour phases. We thus review some possible techniques for Adaptive Mesh...Aller à la page de la contribution
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Dr Daniel FUSTER (Institut D'Alembert, UPMC-CNRS 75005 Paris)12/12/2016 11:00In this work we numerically investigate the effect of heat and mass transfer on the dynamic response of gas-vapor bubbles. The numerical solution of the full non-linear 1D equations is compared with the analytical solution of the equations obtained for the oscillation of an spherical gas/vapor bubble in response of a weak pressure perturbation (linear solution). For a system with known...Aller à la page de la contribution
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Mme Dena Kazerani (Laboratoire Jacques-Louis Lions (UPMC, Paris 6))12/12/2016 11:30In this work, we present a numerical scheme for solving free surface flows. The free surface is modeled using the level-set formulation. Besides, the mesh is anisotropic and adapted at each iteration. This adaptation allows us to obtain a precise approximation for the free- surface location. In addition, it enables us to solve the time-discretized fluid equation only on the fluid domain. The...Aller à la page de la contribution
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Dr Sébastien Tanguy (Institut de Mécanique des Fluides de Toulouse)12/12/2016 12:00Studies on two-phase flows are of interest in many fundamental problems and industrial applications, as the spray formation in internal combustion engine, the bubble formation in heat exchangers, the fluid management in satellites or space launcher tanks, the spray cooling or the interaction of bubbles with acoustic waves. The Direct Numerical Simulation is a powerful tool, which is...Aller à la page de la contribution
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Prof. Stéphane Zaleski (Université Pierre et Marie Curie (Paris))12/12/2016 14:15We discuss recent developments in the Volume-Of-Fluid (VOF) methods, such as the height function method for the approximation of the geometry of the interface, the balanced-force surface tension method, and the methods that conserve mass and momentum at machine accuracy. Applications at high Reynolds number,such as high speed liquid-gas flows, and low Reynolds and low Capillary numbers, are...Aller à la page de la contribution
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Dr Guillaume Bois (CEA (Paris-Saclay))12/12/2016 15:00The Front-Tracking method has been implemented in TrioCFD and improved over the last decade. It has been widely used on large parallel architectures to study incompressible two- phase flows. The permanent increase in computing capabilities allows to perform simulations of fully turbulent bubbly flows in relatively small periodic domains. This talk will be organized in two parts. The...Aller à la page de la contribution
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13. High fidelity anisotropic adaptive FEM towards physical couplings occurring in turbulent boilingDr Elie Hachem12/12/2016 16:30We propose in this work an adaptive variational multiscale method for complex multiphase flows with surface tension: applications to 3D bubble dynamics, turbulent boiling and solid quenching with experimental comparisons will be presented. A new conservative level-set method is used to provide a precise position of the interfaces. An implicit implementation of the surface tension in the...Aller à la page de la contribution
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Dr François-Xavier Demoulin (CORIA)12/12/2016 17:00DNS[1], LES [2] and RANS [3] modelling of atomization have been developed for the last decade in our laboratory with a particular attention devoted on the behavior of the interface. In particular model equations for the liquid-gas surface density have been proposed based on the pioneering work of Borghi and Vallet [4]. The purpose of this approach is to determine the surface density that we...Aller à la page de la contribution
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Prof. Rémi Abgrall (Université de Zürich)12/12/2016 17:30Since the celebrated Lax Wendroff theorem, it is known that the right way of discretising systems of hyperbolic equations written in conservation form is to use a flux formulation. However, in many occasions, the relevant formu- lation, from an engineering point of view, is not to consider this conservative formulation but one non conservative form. For example, with standard notations, a...Aller à la page de la contribution
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Dr Hélène Mathis (Université de Nantes)13/12/2016 09:00We propose a model of liquid-vapor phase transition including metastable states of the van der Waals Equation of State. The first part of the talk concerns the thermodynamics model. Following the second principle, the problem boils down to a minimization problem with constraints of the mixture energy. This ”static” description allows to recover the classical equilibria: pure...Aller à la page de la contribution
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Prof. Richard Saurel (Université Aix-Marseille)13/12/2016 09:45Conventional models of capillary fluids with phase transition consider linked thermodynamics and capillarity. Such coupling has serious consequences, such as: - sound propagation, undefined in some critical regions, - very thin interfaces, causing serious issues in practical computations. In the present talk an approached based on hyperbolic systems with relaxation is promoted to...Aller à la page de la contribution
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Prof. Laurette Tuckerman (Ecole Supérieure de Physique et de Chimie Industrielle (Paris))13/12/2016 11:00In 1831, Faraday described the standing wave patterns that form on the surface of a layer of fluid subjected to periodic vertical vibration. These waves usually take the form of stripes, squares, or hexagons. However, other phenomena have been observed numerically, such as quasipatterns, supersquares, heteroclinic cycles, and oscillons. Until recently, numerical simulation of Faraday...Aller à la page de la contribution
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Mme Marie Béchereau (Ecole normale supérieure de Cachan (Paris-Saclay))13/12/2016 11:45Two-fluid extensions of Lattice Boltzmann methods with free boundaries usually consider "microscopic'' pseudopotential interface models. In this paper, we rather propose an interface-capturing Lattice Boltzmann approach where the mass fraction variable is considered as an unknown and is advected. Several works have reported the difficulties of LBM methods to deal with such two-fluid...Aller à la page de la contribution
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Dr Laurent Martin Witkowski13/12/2016 14:30The free surface deformation generated by a disk rotating at the bottom of a container partially filled with fluid is an exciting challenge for numerical simulations. The shape of the free surface has shown surprising patterns in experiments performed by different research groups. However, for many regimes (non axisymmetric, dewetted disk, sloshing), an accurate comparison with numerical...Aller à la page de la contribution
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Mme Saira Pineda13/12/2016 15:00A multiphase model developed in SPH-ALE is used to simulate the collapse of a gas bubble in water. This model does not diffuse the interface and guarantees the continuity of normal velocity and pressure at the interface between both fluids. This scheme is able to deal with interfaces of simple contact where normal velocity is continuous. The model solves the mass, momentum and energy...Aller à la page de la contribution
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Dr Bérénice Grec13/12/2016 15:30Thermohydraulic codes used in industry are based on the resolution of compressible Navier-Stokes equations in which acoustic waves are taken into account. This allows to describe fluid flows at any Mach number. However, many difficulties may arise in terms of CPU time, robustness and accuracy in the low Mach number regime. In this regime, an asymptotic expansion with respect to the Mach...Aller à la page de la contribution
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