Transcript Some Specific Projects

US France Young Engineering
Scientists symposium
Some Specific Projects
Modeling and HPC
US France Young Engineering
Scientists symposium
The Life Sciences Session
Life Sciences Session
Common features
complex problems (multiphase, multiphysics,
multidomain, multi scale),
often "early stage" in modelization.
Life Sciences Session
Common interest
Four subjects
Soft tissue/fluid (medical image driven problems);
Contact model/moving boundaries;
Concentrate suspension;
Complex geometry and (medical...) imaging.
Medical image driven problems
Georges Biros, Didier Auroux, Marcela Szopos,
Benjamin Mauroy, Mourad Ismail, Boyce Griffith.
Right now:
integration of existing codes in an open source
framework;
development of benchmarks for arterial flows;
sharing image-driven model datasets (when
possible);
development of novel parameter estimation
algorithms.
Contact model /moving boundaries
Judith Hill, Vincent Martin, Marcela Szopos, Arnaud
Ducrot, Olivier Saut, Benjamin Mauroy, Boyce Griffith.
Right now:
a discussion of methods for moving
boundaries (we all use different ones)
a beginning of a discussion on the theory
behind the contact problem (what's the
right thing to do).
Concentrate suspension
Mourad Ismail, Judith Hill, Olivier Saut, Benjamin
Mauroy.
Right now:
compare different numerical methods for
complex fluids simulation
include some US researchers in our ANR
project "MOSICOB" on numerical
simulation of complex fluids.
share experimental data for validation of
numerical methods.
Complex geometry and imaging
Olivier Saut, Boyce Griffith, Arnaud Ducrot.
Right now:
discuss methods for mesh generation;
discuss compare methods for interpolation of
medical data on the mesh (and image
reconstruction).
US France Young Engineering
Scientists symposium
The Algorithm Session
Error estimate-based
adaptivity for fluid structure
problems
Martin Vohralik, Virginie
Bonnaillie-Noel, Mourad Ismail,
Martin Campos-Pinto, Boyce
Griffith, Sreekanth Pannala
Develop and implement a general parallel adaptive
scheme based on local error estimate for problems
involving fluid structure interactions.
Some of the properties desirable in this scheme are:
a) Optimal geometric and hierarchical adaptivity based
on local error
b) Load balanced to ensure scalability
c) Amenable to implicit fluid structure coupling
Numerical methods for singular
reaction diffusion equations
arising in population dynamics
Arnaud Ducrot
Mayya Tokman
We want to construct numerical
schemes using the weak formulation
of pray-predator models with
Holling-Tanner like interaction.
The scheme will capture the singular
behaviour of thesolutions
Inverse problems, parameter
estimation and data
assimilation
Didier Auroux
George Biros
In most life and physical sciences, a crucial issue
in the modelisation process is the estimation and
identification of the model parameters (or some boundary
conditions, or some unknown terms in the model
equations). Inverse problem and data assimilation
techniques (e.g. optimal control theory, Kalman filters,
dual variational algorithm) allow us to calibrate the model
parameters from real data sets and identify more
precisely the system state.
We will combine Kalman filters with dual
variational methods to explore novel methodologies for
large scale data assimilation. We will conduct numerical
experiments to compare the new methods with the
existing state of the art.
Development of Parallel
Solvers for Highly Anisotropic
Parabolic Linear Systems
Arising in Resistive MHD and
Radiation Transport
Frederic Magoules
Daniel Reynolds
Bronson Messer
We consider linear systems arising from highly
anisotropic, parabolic differential equations relevant to
fusion plasmas and astrophysical radiation transport. We
will investigate parallel Domain Decomposition
algorithms on these problems. Such approaches may
promise increased robustness over multigrid methods for
highly anisotropic and spatially adaptive systems on such
problems.
US France Young Engineering
Scientists symposium
“Non-life sciences”
and
“Software and libraries”
Sessions
Parallel in Time and Space
Algorithms for Fluid
Mechanics
F. Magoules
K. Evans
G. Staffelbach
R. Mills
Parallel in Time and Space
Algorithms for Fluid Mechanics
• We will investigate computational efficiency improvements for
computational fluid dynamics through an adaptation of the
parallel method both in time and space. First, development of an
implicit solver will allow larger time steps on relatively coarse
grids to create 'seed' values along a time dependent run. The
seed values allow a subsequent refinement of decomposed time
domains to occur in parallel. An investigation of the treatment
will be performed to determine the feasibility of scalability to
500K processors using space and time decomposition.
Combined Finite Element and
Finite Volume Schemes for
Subsurface Flows
Martin Vohralik
Richard Mills
Sreekanta Parmala
Combined Finite Element and Finite
Volume Schemes for Subsurface Flows
Develop and implement a scalable scheme based on
combined Finite Element (FE) and Finite Volume (FV) method
for subsurface flow and transport with full anisotropic
heterogeneous tensor and the following properties:
1.
2.
3.
4.
5.
6.
7.
One unknown/element
Symmetric Positive Definite matrix
With proven existence and uniqueness
General mesh (non-convex, non-matching)
Local conservation
Linear
Discrete maximum principle
Efficient Preconditioning
Strategies for Neutral Particle
Transport
Dinesh Kaushik
Broson Messer
Laura Grigori
Julien Salomon
Efficient Preconditioning Strategies
for Neutral Particle Transport
The neutron transport equation is seven dimensional (three in space,
two in angle, one in energy, and the last in time). The discretized form
of this equation gives rise to massive linear systems that need to be
solved on large-scale parallel machines. In order to do this in
reasonable amount of time, efficient preconditioners are essential. In
this collaborative effort, we will work on custom precondtioners that
take advantage of the matrix structure. These preconditioners will be
applied to the astrophysics (neutrino transport) and nuclear reactor
applications (neutron transport). We will also explore the opportunities
for preconditioning using techniques from parallelization in the time
dimension.
Theoretical Analysis of the
Eigenspectrum of the Dirac
Equation
James Brannick
Virginie Bonnaillie-Noel
Theoretical Analysis of the
Eigenspectrum of the Dirac Equation
•
•
The aim of the project is to analyze the properties of the eigenspectrum of the
Dirac equation of
QCD. Initially, we propose to study the simplified Schwinger model of Quantum
Electrodynamics
with a U(1) potential.
•
The goals will be as follows:
•
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Conduct theoretical analysis to determine the behavior and localization of the
eigenfuntions
Develop a gauge invariant discretization using Finite Elements -current discretizations are essentially limited to finite difference schemes.
Explore the theoretical results using this numerical model.
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Generalize the results obtained for this model to the QCD equation with SU(3) gauge.
Integrating Adaptive Grids with
Nonlinear Solvers for Problems in
Plasma Physics
Martin Compos-Pinto
Mayya Tokman
Daniel Reynolds
Integrating Adaptive Grids with
Nonlinear Solvers for Problems in
Plasma Physics
The presence of complex nonlinear interactions of multiple spacial and
tem- poral scales make numerical solutions of equations such as
Vlasov or MHD a challenging task. To address this problem, it is highly
desirable to construct numerical schemes which integrate efficient
adaptive approaches to discreti- zations in space and time. By
combining expertise of French researchers in time evolution of adaptive
space discretizations and American counterparts in efficient time
integrators for nonlinear systems, we plan to investigate pos- sibilities
for designing innovative numerical methods for problems in plasma
physics.
Exploring Coupling Strategies Using
PALM for Multiphysics Nuclear Reactor
Simulations
Dinesh Kaushik
Gabriel Staffelbach
Laura Grigori
Exploring Coupling Strategies Using
PALM for Multiphysics Nuclear Reactor
Simulations
•
Nuclear reactor core simulations require coupling among different
physics areas such as neutronics, thermal hydraulics, and structural
mechanics. This coupling needs to be accurate (not to compromise
accuracy from each physics component) and parallel (to support largescale simulations). We will explore using PALM software for coupling
mutiphysics codes from Argonne. PALM is developed by the PALM
Team at CERFACS (http://www.cerfacs.fr/~palm/). Various coupling
approaches will be tested with scalability and ease of use in mind. We
will also attempt to construct accurate interpolation schemes and
preconditioning techniques designed for the coupled systems.