Seminar at the

Laboratoire Jacques-Louis Lions

Université Pierre et Marie Curie, Paris


 Philippe G. LeFloch (Paris)

 Jacques Smulevici (Orsay)

Jérémie Szeftel (Paris)

Dates of the Seminar for this Academic year: 

October 9, November 20, December 4, February 12, March 12

+ Conference from May 28 to June 1rst

Monday March 12, 2018

room 15-16 309

 14h  Carla Cederbaum (Tubingen)

On foliations related to the center of mass in general relativity

Abstract.  We will discuss new developments in the analysis of asymptotic foliations by prescribed curvature in relativistic initial data sets with prescribed asymptotic decay, generalizing results by Huisken and Yau. We will relate these foliations to the definition of the center of mass of the initial data sets under consideration. The results presented are joint work with Cortier–Sakovich and with Nerz.

 15h30  Maxime Van de Moortel (Stanford)

Stability and instability in spherical symmetry of Reissner-Nordström black holes for the Einstein-Maxwell-Klein-Gordon model

Abstract. Penrose’s Strong Cosmic Censorship Conjecture is one of the central problems of Mathematical General Relativity. Its proof for the Einstein-Maxwell-Uncharged-Scalar-Field (EMSF) model in spherical symmetry relies on the formation of a Cauchy horizon that is C0 regular but C2 singular for generic Cauchy data. EMSF model however only admits two-ended black holes, unlike its charged analogue that allow for one-ended black holes, relevant to the study of charged gravitational collapse in spherical symmetry. In this talk I will present my work about spherically symmetric charged and massive scalar fields on black holes. This includes a study of the black hole interior, that relates the behavior of fields on the event horizon to the formation of a C0 regular and C2 singular Cauchy horizon. I will also mention my more recent work on the black hole exterior stability, for weakly charged massless scalar fields.


Monday February 12, 2018

room 15-16 309

 14h Shadi Tahvildar-Zadeh (Rutgers)

General relativity at the subatomic scale

Abstract. The idea that General Relativity (GR) may have something to say about the subatomic world is about as old as GR itself, but very few physicists have taken it seriously, and little is known rigorously about it. In this talk I use the problem of the “general- relativistic Dirac spectrum of Hydrogen” to convey the conceptual and technical issues one is up against, and survey recent results obtained in collaboration with my colleague Michael Kiessling and by some of our students and postdocs.

 15h30 Thomas W. Johnson  (Cambridge)

Abstract. I shall discuss the linear stability of the Schwarzschild family of black holes as solutions to the Einstein vacuum equations when expressed in a generalised wave gauge, a result which complements the recent work of Dafermos, Holzegel and Rodnianski in a similar vein as the pioneering result of Lindblad and Rodnianski complemented the monumental achievement of Christodoulou and Klainerman in establishing the global nonlinear stability of the Minkowski space. The proof relies on classical insights regarding the linearised Einstein equations about the Schwarzschild family, in particular the decoupling of certain gauge-invariant scalars into the Regge—Wheeler and Zerilli equations, and recent advances for the linear wave equation on the Schwarzschild exterior, both of which shall be reviewed.


Monday December 4, 2017

room 16-26 113

 14h Siyuan Ma (Potsdam)

On Maxwell field and linearized gravity in Kerr

Abstract.  I will consider both Maxwell field and linearized gravity on Kerr backgrounds, and present recent results in obtaining energy and Morawetz estimates for the extreme Newman-Penrose components.

 15h30 Claudio Paganini (Potsdam)

Mode stability on the real axis

Abstract.  I will discuss a generalization of the mode stability result of Whiting (1989) for the Teukolsky equation for the case of real frequencies. The main result states that a separated solution of the Teukolsky equation governing massless test fields on the Kerr spacetime, which is purely outgoing at infinity, and purely ingoing at the horizon, must vanish.


Monday November 20, 2017

room 16-26 113

 14h Frederico Pasqualotto (Princeton)

Nonlinear stability for the Maxwell–Born–Infeld system on a Schwarzschild background

Abstract. The Maxwell–Born–Infeld (MBI) theory is a hyperbolic system of PDEs which describes nonlinear electromagnetism. Due to its tensorial and quasilinear nature, this system can be seen as a nonlinear model problem to study the stability properties of solutions to the Einstein vacuum equations. In this talk, I will present a nonlinear stability result for the MBI system on a fixed Schwarzschild background, when the initial data are constrained to be small. A crucial element of the proof is the observation that some null components of the MBI field satisfy “good” Fackerell–Ipser equations, as in the linear Maxwell case. However, in the MBI case, these equations are coupled through cubic nonlinear right hand sides, which contain all components of the MBI field. In order to resolve the coupling, we prove high-order energy decay and, subsequently, pointwise decay for all the components of the MBI field. This is achieved through the application of many ideas developed in recent years, regarding the decay of linear fields.

 15h30 Volker Schlue (Paris)

On `hard stars’ in general relativity

Abstract. I will review the classical picture of gravitational collapse in spherical symmetry, from the Oppenheimer-Snyder model (1939) to Christodoulou’s two phase model (1995). I will then turn to the possible end states of gravitational collapse, in particular discuss non-trivial static solutions to the two-phase model, which are idealized models of neutron stars. The main results concern a variational characterization of hard stars, and I will outline their relevance for the orbital stability problem of neutron stars in spherical symmetry. I hope to conclude with a discussion of the various remaining problems that have to be overcome for a global in time result, in particular related to possible phase transitions in this model.


Monday October 9, 2017

room 15/16-309

 14h Daniel Monclair (Orsay)

Attractors in spacetimes and time functions

Abstract.  A time function on a Lorentzian manifold is a continuous real valued function which is increasing along all future directed causal curves. A result of Hawking states that the existence of a time function is equivalent to stable causality, i.e. the impossibility of generating timelike loops even after small perturbations of the metric. We will discuss a construction of time functions which is quite different from Hawking’s construction, in the sense that it produces functions that still have interesting properties for non stably causal spacetimes (while Hawking’s time functions fail to be continuous without stable causality). Our approach is based on a notion of attracting sets in spacetimes, following the work of Conley on Lyapunov functions.

 15h30 The-Cang Nguyen (Paris)

Global dispersion of self-gravitating massive matter in spherical symmetry

Abstract.  We study massive matter fields evolving under their own gravitational field and we generalize results established by Christodoulou for the spherically symmetric evolution of massless scalar fields governed by the Einstein equations. We encompass both Einstein’s theory and the f(R)-theory of modified gravity defined from a generalized Hilbert-Einstein functional depending on a nonlinear function f(R) of the spacetime scalar curvature R. This is a joint work with P.G. LeFloch and F. Mena.



Seminar at the

Laboratoire Jacques-Louis Lions

Université Pierre et Marie Curie, Paris


 Philippe G. LeFloch (Paris)

 Jacques Smulevici (Orsay)

Jérémie Szeftel (Paris)

Dates of the Seminar:

January 30, February 27, March 20, April 10, May 22, June 6, June 19, July 4


Monday January 30, 2017

room 15/25-104


 14h Georgios Moschidis (Princeton, USA)

The scalar wave equation on general asymptotically flat spacetimes. Stability and instability results

Abstract. We will examine how certain geometric conditions on general asymptotically flat spacetimes (M,g) are related to stability or instability properties of solutions to the scalar wave equation on M. First, in the case when (M,g) possesses an event horizon with positive surface gravity and an ergo-region which is sufficiently small in terms of the near-horizon geometry, we will prove a logarithmic decay result for solutions to  the wave equation, provided a uniform energy boundedness estimate holds. This result, applicable also in the absence of a horizon and an ergo-region, generalizes a result of Burq for the wave equation on the complement of an arbitrary compact obstacle in flat space. We will then apply the methods developed for the proof of this result in obtaining a rigorous proof of Friedman’s ergosphere instability for scalar waves in the case when (M,g) possesses an ergo-region and no event horizon.

 15h30 Xavier Lachaume (Tours)

The constraint equations of scalar tensor and Lovelock theories

Abstract. The ADM decomposition is the projection of the Einstein field equations on a spacelike foliation of the spacetime. It gives the constraint equations that must necessarily be satisfied by a riemannian metric and a 2-form to be the initial data of an Einstein spacetime. In this talk, we shall introduce some modified gravity theories: the scalar-tensor and Lovelock theories, and see how they behave under the ADM decomposition. We shall examine their constraint equations, and solve them in particular cases. This involves the study of whether a certain function of the elementary symmetric polynomials is concave or not.


Monday February 27, 2017

room 15/16-309


14h Mokdad Mokdad (Brest)

Conformal scattering for Maxwell fields on Reissner-Nordstrøm-de Sitter spacetimes

Abstract. The Reissner-Nordstrøm-de Sitter spacetime models a spherically symmetric charged and non-rotating black hole in the presence of a positive cosmological constant. Depending on the parameters of the metric, this spacetime can have up tothree distinct event horizons. In the case of three horizons, we develop a scattering theory for Maxwell fields using the conformal geometric approach initiated by Penrose and Friedlander and referred to as conformal scattering. The idea is that a complete scattering theory is equivalent to the well-posedness of the Goursat problem (characteristic Cauchy problem) at the null boundary of the conformal manifold. Decay estimates obtained by geometric energy inequalities are essential tools for closing the estimates that allow the construction of the scattering operator : their role is to prove that energy cannot accumulate at timelike infinity, which can be understood as a weak form of Huygens’ principle.

15h30 Annalaura Stingo (Paris 13)

Global existence and asymptotic behavior for small solutions to 1D quasi-linear cubic Klein-Gordon equations

Abstract. Let u be a solution to a quasi-linear cubic Klein-Gordon equation, with smooth, small Cauchy data. It is known that, under a suitable condition on the nonlinearity, the solution is global-in-time for compactly supported Cauchy data. We prove that the result holds even when data are not compactly supported but only decay like 1/r at infinity, combining the method of Klainerman vector fields with a semiclassical normal forms method introduced by Delort. Moreover, we get a one-term asymptotic expansion for the solutions and establish a modified scattering property.

Monday March 20, 2017

room 15/16-309

14h Dominic Dold (Cambridge, UK)

Exponentially growing mode solutions to the Klein-Gordon equation in Kerr-AdS spacetimes

Abstract. We consider solutions to the Klein-Gordon equation in the black hole exterior of Kerr-AdS spacetimes. It is known that, if the spacetime parameters satisfy the Hawking-Reall bound, solutions (with Dirichlet boundary conditions at infinity) decay logarithmically. We shall present our recent result of the existence of exponentially growing mode solutions in the parameter range where the Hawking-Reall bound is violated. We will discuss various boundary conditions at infinity.

Monday April 10, 2017

room 15/25-101

14h Bruno Premoselli (Bruxelles)

Instability of focusing initial data sets in high dimensions

Abstract. We will investigate blow-up properties for a class of initial data sets for the Einstein equations obtained from the conformal method in a scalar-field theory. In dimensions larger than 6, and when some stability conditions on the physics data are not satisfied, we will show that the conformal method produces blowing-up families of initial data sets. The proof of this result combines constructive variational methods with a priori asymptotic analysis blow-up techniques.

Monday May 22, 2017

exceptionally taking place at IHES

and co-organized with S. Klainerman (Princeton)

14h Jan Sbierski  (Cambridge, UK)

The inextendibility of the Schwarzschild spacetime as a Lorentzian manifold with a continuous metric

Abstract. The maximal analytic Schwarzschild spacetime is manifestly inextendible as a Lorentzian manifold with a twice continuously differentiable metric. In this talk I will describe how one proves the stronger statement that the maximal analytic Schwarzschild spacetime is inextendible as a Lorentzian manifold with a continuous metric. The investigation of low-regularity inextendibility criteria is motivated by the strong cosmic censorship conjecture in general relativity.

15h30 Grigorios Fournodavlos (Cambridge, UK)

Dynamics of the Einstein equations near a Schwarzschild singularity

Abstract.  We will discuss dynamical properties of the Schwarzschild interior, backwards and forwards (in time) with respect to the initial value problem for the Einstein vacuum equations.

Tuesday June 6, 2017

room 15/16-309

14h Dejan Gajic (London)

Precise asymptotics for the wave equation on stationary, asymptotically flat spacetimes

Abstract.  The late-time behaviour of solutions to the wave equation on a large class of asymptotically flat spacetimes does not conform to the strong Huygens principle. Instead, it is governed by polynomially decaying “tails”, as first discovered heuristically by Price. Their presence plays an important role in the study of singularities in black hole interiors. I will discuss a method for proving the precise leading-order asymptotics for the wave equation on these spacetimes and in the process I will introduce new energy decay estimates to obtain sharp decay rates that go beyond those obtained via traditional vector field methods. This talk is based on joint work with Yannis Angelopoulos and Stefanos Aretakis.

15h30 Cécile Huneau (Grenoble)

High frequency back reaction for the Einstein equations under polarized U(1) symmetry

Abstract. It has been observed by physicists (Isaacson, Burnett, Green-Wald) that metric perturbations of a background solution, which are small amplitude but with high frequency yield at the limit to a non trivial contribution which corresponds to the presence of an energy impulsion tensor in the equation for the background metric. This non trivial contribution is of due to the nonlinearities in Einstein equations, which involve products of derivatives of the metric. It has been conjectured by Burnett that the only tensors which can be obtained this way are massless Vlasov, and it has been proved by Green and Wald that the limit tensor must be traceless and satisfy the dominant energy condition. The known exemples of this phenomena are constructed under symmetry reductions which involve two Killing fields and lead to an energy impulsion tensor which consists in at most two dust propagating in null directions. In this talk, I will explain our construction, under a symmetry reduction involving one Killing field, which lead to an energy impulsion tensor consisting in N dust fields propagating in arbitrary null directions. This is a joint work with Jonathan Luk (Stanford).

Monday June 19, 2017

room 15/16-309

14h Elena Giorgi (Columbia)

On the rigidity problem of black holes in general relativity

Abstract.  The rigidity problem in General Relativity consists in showing that an (electro)vacuum, asymptotically flat and stationary spacetime is isometric to Kerr(-Newman). The problem was solved for analytic manifolds by Hawking in the so called “no-hair theorem”. We overview the known results related to the rigidity problem for Ricci flat smooth manifolds. In the non-analytic case, Ionescu-Klainerman extended the Hawking Killing field along the horizon to the outer domain of dependence. This was done through a unique continuation procedure, relying on Carleman estimates. We generalize the result to the case of Einstein equation coupled with Maxwell equations. Finally, we summarize what is known in the case of degenerate horizons, which corresponds to the extremal Kerr.

Monday July 3, 2017

exceptionally taking place at IHES

and co-organized with S. Klainerman (Princeton)

14h Steffen Aksteiner (Potsdam)

From operator identities to symmetry operators

Abstract.  The hidden symmetry of the Kerr spacetime, encoded in its pair of conformal Killing-Yano tensors, implies hidden symmetries for various test fields on such a background. Starting from certain natural operator identities we derive two such symmetries of the linearized Einstein operator. The first one is of differential order four and the relation to the classical theory of Debye potentials as well as to the Chandrasekhar transformation will be explained. The second one is of differential order six and related to the separability of an integrability condition to the linearized Einstein equations — the Teukolsky equation. Advanced symbolic computer algebra tools for xAct were developed for this purpose and if time permits, I will give an overview on the current status.

15h30 Arick Shao (London)

Unique continuation of waves on asymptotically Anti-de Sitter spacetimes

Abstract. In theoretical physics, it is often conjectured that a correspondence exists between the gravitational dynamics of asymptotically Anti-de Sitter (AdS) spacetimes and a conformal field theory of their boundaries. In the context of classical relativity, one can attempt to rigorously formulate such a correspondence statement as a unique continuation problem for PDEs: Is an asymptotically AdS solution of the Einstein equations uniquely determined by its data on its conformal boundary at infinity? In this presentation, we establish a key step: we prove such a unique continuation result for wave equations on fixed asymptotically AdS spacetimes. In particular, we highlight the analytic and geometric features of AdS spacetime which enable this uniqueness result, as well as obstacles preventing such a result from holding in other cases. If time permits, we will also discuss some applications of this result toward symmetry extension and rigidity theorems.



Seminar at the

Laboratoire Jacques-Louis Lions

Université Pierre et Marie Curie, Paris


 Philippe G. LeFloch (Paris)

 Jacques Smulevici (Orsay)

Jérémie Szeftel (Paris)

 This Fall: October 10, November 21, and December 12, 2016


Monday October 10, 2016

room 15/25-104


 14h Peter Hintz (Berkeley)

Nonlinear stability of Kerr-de Sitter black holes

Abstract. In joint work with András Vasy, we recently established the stability of the Kerr-de Sitter family of black holes as solutions of the initial value problem for the Einstein vacuum equations with positive cosmological constant, for small angular momenta but without any symmetry assumptions on the initial data. I will explain the general framework which enables us to deal systematically with the diffeomorphism invariance of Einstein’s equations, and thus how our solution scheme finds a suitable (wave map type) gauge within a carefully chosen finite-dimensional family of gauges; I will also address the issue of finding the mass and the angular momentum of the final black hole.

 15h30 Stefan Czimek (Paris)

An extension procedure for the constraint equations

Abstract. In this talk we present a new extension procedure for the maximal constraint equations of general relativity, motivated by applications to the Cauchy problem. Given a small solution on the unit ball, we can extend it to an asymptotically flat global solution. The main features are that our extension procedure does not need a gluing region, preserves regularity and works in weak regularity. For the proof, we use new methods to solve the prescribed divergence equation for the second fundamental form and the prescribed scalar curvature equation for the metric. We use the under-determinedness of the constraint equations to conserve regularity.



Monday November 21, 2016

room 15/16-413


14h The-Cang Nguyen (Paris)

Progress and recent results for the conformal equations

Abstract. The presentation will be divided into two parts. First, I will introduce the conformal equations and present recent results for these equations as well as questions arising naturally. In a second part, I will talk about the “half-continuity method” and explain how to use this method for giving answers to the questions posed in the first part.

15h30 Volker Schlue (Paris)

On the nonlinear stability of expanding black hole cosmologies



Monday December 12, 2016

room 15/25-102


14h Michał Wrochna (Grenoble)

The quantum stress-energy tensor and its intricate relationship with spacetime geometry

Abstract. It is widely believed that at low energies, quantum gravity should yield an effective theory described by Einstein equations with a stress-energy tensor made of averaged fluctuations of quantum fields. The construction of that stress-energy tensor is however very problematic and its intricate dependence on spacetime geometry results in highly non-linear equations that possess no qualitative theory to date. In this talk I will review this problem as a motivation for improving the construction of linear Klein-Gordon quantum fields, and discuss recent progress that allows for a better control of the dependence on the spacetime metric (partly based on joint work with Christian Gérard).

15h30 Guillaume Idelon-Riton (Regensburg)

Some results about the scattering theory for the massive Dirac fields in the Schwarzschild-Anti-de Sitter space-time

Abstract.  I will first give a brief presentation of the Schwarzschild-Anti-de Sitter spacetime and of some of its geometrical properties that will concern us. Then I will present the massive Dirac equation in this space-time and first study the Cauchy problem which is not completely obvious since our spacetime is not globally hyperbolic. I will then give a result concerning the asymptotic completeness for these fields. By means of a Mourre estimate, it is possible to obtain that the minimal velocity for these fields is 1. I will then show that our dynamics behaves in asymptotic regions like a transport at unit speed in the direction of the black hole. In a third part, I will study the local energy decay for these fields. First, using the existence of exponentially accurate quasi-modes, I will show a logarithmic lower bound on the local energy decay which is in accordance with the results of G. Holzegel and J. Smulevici in the Kerr-Anti-de Sitter spacetime for the Klein-Gordon fields. In order to obtain an upper bound, I will prove the existence of resonances and give some tools in order to localize them.



Workshop 2016

“Modeling and Computation of Shocks and Interfaces”

Laboratoire Jacques-Louis Lions

Université Pierre et Marie Curie, Paris


 Philippe G. LeFloch (Paris)

 Charalambos Makridakis  (Brighton)

Supported by the ModCompShock ITN project

and a project PICS CNRS

 Dec. 6 around 1:30pm to Dec. 8 around 1pm

Main speakers

Remi Abgrall (Zurich)

Benjamin Boutin (Rennes)

Christophe Chalons (Versailles)

Sergey Gavrilyuk (Marseille)

Charalambos Makridakis (Brighton)

Pierangelo Marcati (L’Aquila)

Siddhartha Mishra (Zurich)

Carlos Pares (Malaga)

Nils Risebro (Oslo)

Giovanni Russo (Catania)

Lev Truskinovsky (Palaiseau)


Titles of the lectures

Remi Abgrall

Benjamin Boutin Numerical boundary layers for linear hyperbolic IBVP and semigroup estimate

Christophe Chalons On the computation of non conservative products and cell averages in finite volume methods

Makridakis Charalambos  Energy/entropy consistent computational methods

Sergey Gavrilyuk Shock-droplet interaction via a new hyperbolic phase field model

Pierangelo Marcati Splash singularities for incompressible viscoelatic fluids 

Siddhartha Mishra Statistical solutions of systems of conservation laws

Carlos Pares Entropy stable schemes for degenerate convection-diffusion equations

Nils Risebro  Numerical methods for scalar conservation laws with a stochastically driven flux

Giovanni Russo Shock capturing schemes for all Mach number flow in gas dynamics

Lev Truskinovsky Solitary waves in the FPU lattice: from quasi-continuum to anti-continuum limit

Schedule of the workshop

Tuesday afternoon

2pm-2:45pm: C. Makridakis

2:45-3:30pm: C. Pares

3:30pm: coffee break

4pm-4:45pm G. Russo

Wednesday morning

10am-10:45am: S. Gavrilyuk

10:45am: coffee break

11:15am: C. Chalons

Noon: lunch buffet

Wednesday afternoon

2pm-2:45pm R. Abgrall

2:45pm-3:30pm S. Mishra

3:30am coffee break

4pm L. Truskinovsky

Thursday morning

9:30am-10:15am N. Risebro

10:15am coffee break

10:45am B. Boutin

11:30am P. Marcati

12:15 lunch buffet (end of the workshop)

Participants to the workshop

Other practical informations

The workshop will take place in the main lecture room 309 of the Laboratoire Jacques-Louis Lions, Université Pierre et Marie Curie, which is located in the building 15-16.

Address: 4 Place Jussieu, 75258 Paris. Subway station: Jussieu.

List of hotels in the vicinity of the university

11th DFG–CNRS WORKSHOP Micro-Macro Modeling and Simulation of Liquid-Vapor Flows

organized with the financial support of


Wednesday March 2nd, 2016 (afternoon) 

to  Friday March 4th, 2016 (at noon)

Laboratoire Jacques-Louis Lions, Université Pierre et Marie Curie, 4, Place Jussieu, Paris. Subway station: Jussieu 

Lecture room 15-16 — 309



Nina Aguillon (Paris) 

Christophe Berthon (Nantes)

Christophe Chalons (Versailles) 

Frédéric Coquel (Palaiseau)

Johannes Daube (Freiburg)

Bruno Després (Paris)

Christian Dickopp (Aachen)

Florence Drui (Châtenay-Malabry) 

Robert Eymard  (Marne-La-Vallée)

Jan Giesselman (Stuttgart)

Philippe Helluy (Strasbourg)

Mirko Kraenkel (Freiburg)

Dietmar Kroener (Freiburg)

Rüdiger Müller (Berlin)

Carlos Pares (Malaga)

Arnold Reusken (Aachen)



Main organizer

Philippe G. LeFloch (Paris)


Dietmar Kroener (Freiburg)

Frédéric Coquel (Palaiseau)



Wednesday afternoon (Chairman P.G. LeFloch) 


14h30 -15h Robert Eymard  (Marne-La-Vallée)
15h – 15h30 Jan Giesselman (Stuttgart)
15h30 – 16h Coffee break
16h-16h30 Philippe Helluy (Strasbourg)
16h30-17h Mirko Kraenkel (Freiburg)


Thursday morning  (Chairman Jan Giesselman)


10h-10h30 Christophe Berthon (Nantes)
10h30-11h Johannes Daube (Freiburg)
11h-11h30 Coffee break 
11h30-12h Christophe Chalons (Versailles)
12h-12h30 Dietmar Kroener (Freiburg)
12h30-14h30 Lunch break


Thursday afternoon (Chairman F. Coquel) 


14h30-15h Bruno Després (Paris)
15h-15h30 Arnold Reusken (Aachen)
15h30-16h Coffee break
16h-16h30 Nina Aguillon (Paris)
16h30-17h Rüdiger Müller (Berlin)


Friday morning (Chairman D. Kroener)


10h-10h30 Carlos Pares (Malaga)
10h30-11h Florence Drui (Châtenay-Malabry)
11h-11h30 Coffee break
11h30-12h Christian Dickopp (Aachen)
12h-12h30 Frédéric Coquel (Palaiseau)




Nina Aguillon (Paris)  Numerical approximation of hyperbolic systems containing an interface 
Abstract. We present an approach to approximate numerically the solution of coupled hyperbolic conservation laws. The coupling is achieved through a fixed interface, in which interface conditions are linking the traces on both sides. The main interest of the scheme is that it does not use the knowledge of the solution to the Riemann problem, and hence it is quite flexible and easy to implement. The idea of the scheme is to balance the effects ot the waves that enter the interface, in order to numerically mimic the structure of the Riemann problem. The scheme is well balanced with respect to all the piecewise equilibria associated with the interface conditions. If one of the interface condition is the conservation of a conserved variable, the scheme maintains it exactly. We will present a detailed analysis in the classical case, and a variety of test cases assessing the quality of the method. This is a joint work with Raul Borsche (Technische Universität Kaiserslautern)

Christophe Berthon (Nantes)  Numerical convergence rate for a diffusive limit of hyperbolic systems: p-system with damping


Christophe Chalons (Versailles)  On all regime Lagrangian-remap numerical schemes for compressible fluid systems
Abstract. It is the purpose of this contribution to provide an overview on recent advances in the development of all-regime Lagrange-Remap numerical schemes for compressible fluids systems with source terms. We will consider in particular the case of large friction coefficients and the case of low-Mach numbers. More precisely, we will present a discretization strategy for gas dynamics equations for unstructured grids based on a Lagrange-Remap approach that does not involve any moving mesh. A natural semi-implicit extension of the method that allows to remain stable under a CFL condition involving only the material velocity will be given, together with an extremely simple modification that allows to provide an accurate and stable solver for simulations involving low-Mach regions in the flow. The stability properties of the proposed schemes and several numerical experiments will be presented. This contribution is based on a series of joint works with Mathieu Girardin and Samuel Kokh. These works were performed during M. Girardin’s PhD thesis.


Johannes Daube (Freiburg)  Sharp interface limit for the Navier–Stokes–Korteweg model

Abstract. The Navier–Stokes–Korteweg model, an extension of the compressible Navier–Stokes equations, is a diffuse interface model for liquid-vapour flows which allows for phase transitions. In the model, a small parameter represents the thickness of an interfacial area, where phase transitions occur. Its static version was studied by Hermsdoerfer, Kraus and Kroener and the corresponding interface conditions were obtained. Assuming convergence of an associated energy functional to a suitable surface measure, we will perform the sharp interface limit in the dynamic case. More precisely, by means of compactness, we will ensure that solutions to the diffusive Navier-Stokes-Korteweg equations converge to solutions of an appropriate sharp interface model as the interface thickness tends to zero. This is joint work with H. Abels (Regensburg), C. Kraus (Wuerzburg-Schweinfurt) and D. Kroener (Freiburg).


Bruno Després (Paris) Modeling uncertainties with  kinetic equations
Abstract: The modeling of uncertainties is fundamental in industry and in CFD. For  nonlinear equations, it   questions the compatibility of L1-BV techniques (for conservation laws)  with L2 approaches (for the uncertainties). I will review recent progresses on the modeling at the kinetic level (with B. Perthame), and present recent ideas  which show connection of the so-called kinetic polynomials with optimal control (with E. Treat).


Christian Dickopp (Aachen) Coupling of (elastic)-plastic solids with compressible two-phase fllows for cavitation damaging
Abstract. As a model problem to investigate cavitation damaging the collapse of a single gas bubble collapsing near to an elastic or elastic-plastic solid wall is simulated numerically. This transient three-phase system is  modeled by the compressible Euler equations completed by a stiffened gas law for both fluids, where the liquid and the gas phase are distinguished  by a level set approach, and either the pure elastodynamical equations for a linear-elastic solid or an extension to describe plastic effects. A weak coupling strategy connects the alternating calculations of the fluid solver and  the solid solver using transient boundary conditions that are updated by the other solver.


Florence Drui (Châtenay-Malabry) A hierachy of homogeneous two-fluid models and numerical methods for simulating various regimes of two-phase flows
Abstract. Compressible two-fluid models offer a potential solution for simulating separated two-phase flows configurations. On the other hand, a specific family of such models has been developed for the regime of dispersed gas bubbles and show good agreement with experiments in the case of small acoustic perturbations. On the way to connect both types of flows, we propose here a hierarchy of homogeneous two-fluid models. Starting with Hamilton’s variational principle and adding thermodynamically consistent dissipative structures, we built a new connected hierarchy, each level of which being mathematically well-posed. Every new relaxation small parameter is physically identified through acoustic linearization and analysis of the systems dispersion relations. Furthermore, numerical methods based on finite volume schemes are developed so as to preserve the properties of the models at the continuous level and to asymptotically handle the transition from each subsystem to another. Finally, simulations of simple academic configurations are performed and show the expected properties of the first models of the hierarchy, the numerical methods and dynamically adaptive mesh techniques with the potential for massively parallel simulations.


Robert Eymard  (Marne-La-Vallée) Convection and total variation flow
Abstract. We consider a simplified model, related to the flow of a nonNewtonian fluid. This simplified model consists in a scalar nonlinear hyperbolic equation, regularized by the total variation flow operator (or 1-Laplace operator). We give an entropy weak formulation, for which we prove the uniqueness of the solution using the doubling variable technique. We provide an existence result using the convergence of a numerical scheme, a splitting scheme where the hyperbolic flow is treated with finite volumes and the total variation flow with finite elements. Finally, some numerical simulations in 1D and 2D are presented. This work is a joint work with F. Bouchut and D. Doyen.


Jan Giesselman (Stuttgart) A priori error analysis of DG approximations of two-phase flows

Abstract. In this talk we consider a one dimensional  model for isothermal two-phase flows using Lagrangian coordinates. The model is of diffuse interface type with a non-monotone pressure law. We will present a priori error analysis of a semi-discrete discontinuous Galerkin method, which satisfies a discrete version of the energy inequality which is valid on the continuous level. It also satisfies a relative energy type stability theory. Combining this stability framework with suitable projection operators for the exact solution allows us to derive optimal order error estimates. We will also present numerical results obtained using a fully-discrete version of the scheme, which validate our theoretical results.


Philippe Helluy (Strasbourg) Task-based parallelization of a transport discontinuous Galerkin solver and applications.
Abstract. We present an implicit discontinuous Galerkin solver for the transport equation. Due to the upwind nature of the numerical flux, the linear system in the implicit step is block triangular. The scheme is thus well adapted to a task-based implementation. We present such an implementation using the StarPU library and we  discuss applications to fluid dynamics.


Mirko Kraenkel (Freiburg) Discontinuous Galerkin schemes for the Navier-Stokes-Allen-Cahn system


Dietmar Kroener (Freiburg) Conservation laws on surfaces


Rüdiger Müller (Berlin)  The Lippmann equation for liquid metal electrodes
Abstract. The Lippmann equation is considered as universal relationship between interfacial tension, double layer charge, and cell potential. Recently we have derived a general thermodynamically consistent model for electrochemical interfaces, which shows a remarkable agreement to single crystal experimental data. In this talk, we apply the model to a curved liquid metal electrode in contact with an electrolyte. By matched asymptotic analysis we obtain the Lippmann equation whenever the Debye length is small compared to electrode curvature radius. The interfacial tension of the Lippmann equation is composed of the surface tension of our general model, and additional contributions arising from the adjacent space charge layers. Comparison with experimental data of several mercury-electrolyte interfaces confirms the theoretical results. This is a joint work with Wolfgang Dreyer, Clemens Guhlke, and Manuel Landstorfer.


Carlos Pares (Malaga) Nonconservative products and Shallow Water models: an overview
Abstract. Many hyperbolic nonlinear PDE systems that include source terms and nonconservative products arise in the simulation of geophysical flows by means of depth-averaged models.  In this talk, a review of the numerical techniques developed in last years by my group of research and collaborators to solve this type of systems will be presented together with a discussion of the main difficulties  and challenges in this field. Some applications to the simulation of real flows will be shown to illustrate this topic.


Arnold Reusken (Aachen) Space-time unfitted FEM for problems with moving discontinuities
Abstract. In this talk we will discuss unfitted finite element methods (or CutFEM) in  a space-time setting. The motivation for the development of these methods comes from two-phase incompressible flows. We explain how these techniques can be applied for the accurate discretization of a mass transport equation and a two-phase flow (Navier-)Stokes equation. The idea of the method, rigorous error bounds for certain problem classes and results of numerical experiments will be presented.

Partial LIST of Participants
Boris Andreianov       boris.andreianov at lmpt.univ-tours.fr
Robert Eymard            robert.eymard at univ-mlv.fr
Jan Giesselmann      jan.giesselmann@mathematik.uni-stuttgart.de
Philippe Helluy      helluy at math.u-strasbg.fr
Mirko Keaenkel                kraenkel at mathematik.uni-freiburg.de
Bruno Despres          despres at ann.jussieu.fr
Christophe Berthon   christophe.berthon at math.univ-nantes.fr
Philippe LeFloch      contact at philippelefloch.org
Ruediger Mueller       mueller at wias-berlin.de
Arnold Reusken            reusken at igpm.rwth-aachen.de
Carlos Parés       pares at anamat.cie.uma.es
Johannes Daube              hannes at mathematik.uni-freiburg.de
Chalons Christophe christophe.chalons@uvsq.fr
Nina Aguillon      aguillon at ljll.math.upmc.fr
Christian Dickopp      dickopp at web.de
Florence Drui           florence.drui at centralesupelec.fr
Emmanuel Audusse     eaudusse at yahoo.fr
Gautier Dakin                 gautier.dakin at gmail.com
Roland Duclous            roland.duclous at gmail.com
Mehdi Khalloufi                mehdi.khalloufi at mines-paristech.fr
Pierre-Arnaud Raviart      pa at raviart.com
Frederic Coquel      frederic.coquel at cmap.polytechnique.fr
Dietmar Kroener      dietmar at mathematik.uni-freiburg.de 



How to come to the Laboratoire Jacques-Louis Lions

Hotels near the University Pierre et Marie Curie


EARLIER WORKSHOPS “Micro-Macro Modeling and Simulation of Liquid-Vapor Flows”

Tenth Workshop, Freiburg, February 2015

Ninth Workshop, Paris, February 2014

Eight Workshop, Berlin, February 2013

Seventh Workshop, Paris, February 2012

Sixth Workshop, Stuttgart, January 2011

Fifth Workshop, Strasbourg, April 2010

Fourth Workshop, Aachen, February 2009

Third Workshop, Strasbourg, January 2008

Second Workshop, Bordeaux, November 2007

Opening Workshop, Kirchzarten, November 2005

Philippe LeFloch, DIRECTOR OF RESEARCH AT CNRS Email address: pglefloch [at] gmail.com


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