In this paper, we introduce a set of methods for processing and analyzing long time series of 3D images representing embryo evolution. The images are obtained by in vivo scanning using a confocal microscope where one of the channels represents the cell nuclei and the other one the cell membranes. Our image processing chain consists of three steps: image filtering, object counting (center detection) and segmentation. The corresponding methods are based on numerical solution of nonlinear PDEs, namely...

We study a two-grid scheme fully discrete in time and
space for solving the Navier-Stokes system. In the first step, the
fully non-linear problem is discretized in space on a coarse grid
with mesh-size H and time step k. In the second step, the
problem is discretized in space on a fine grid with mesh-size h
and the same time step, and linearized around the velocity uH
computed in the first step. The two-grid strategy is motivated by
the fact that under suitable assumptions, the contribution of
uH...

In this paper, we first construct a model for free surface flows that takes into account the air entrainment by a system of four partial differential equations. We derive it by taking averaged values of gas and fluid velocities on the cross surface flow in the Euler equations (incompressible for the fluid and compressible for the gas). The obtained system is conditionally hyperbolic. Then, we propose a mathematical kinetic interpretation of this system to finally construct a two-layer kinetic scheme...

We consider the system of partial differential equations governing
the one-dimensional flow of two superposed immiscible layers of
shallow water. The difficulty in this system comes
from the coupling terms involving some derivatives of the unknowns
that make the system nonconservative, and eventually nonhyperbolic.
Due to these terms, a numerical scheme obtained by performing an
arbitrary scheme to each layer, and using time-splitting or
other similar techniques leads to instabilities in...

This study concerns some asymptotic models used to compute the flow outside and inside fractures in a bidimensional porous medium. The flow is governed by the Darcy law both in the fractures and in the porous matrix with large discontinuities in the permeability tensor. These fractures are supposed to have a small thickness with respect to the macroscopic length scale,
so that we can asymptotically reduce them to immersed polygonal fault
interfaces and the model finally consists in a coupling between...

This paper is concerned with the finite volume approximation of the p-laplacian equation with homogeneous Dirichlet boundary conditions on rectangular meshes. A reconstruction of the norm of the gradient on the mesh’s interfaces is needed in order to discretize the p-laplacian operator. We give a detailed description of the possible nine points schemes ensuring that the solution of the resulting finite dimensional nonlinear system exists and is unique. These schemes, called admissible, are locally...

This paper is concerned with the finite volume approximation of the p-Laplacian equation with homogeneous Dirichlet boundary conditions on rectangular meshes.
A reconstruction of the norm of the gradient on the mesh's interfaces is needed in order to discretize the p-Laplacian operator. We give a detailed description of the possible nine points schemes ensuring that the solution of the resulting finite dimensional nonlinear system exists and is unique. These schemes, called admissible, are locally...

This paper is concerned with the numerical approximation of Cauchy problems for one-dimensional nonconservative hyperbolic systems. The theory developed by Dal Maso et al. [J. Math. Pures Appl.74 (1995) 483–548] is used in order to define the weak solutions of the system: an interpretation of the nonconservative products as Borel measures is given, based on the choice of a family of paths drawn in the phase space. Even if the family of paths can be chosen arbitrarily, it is natural to require this...

This paper is devoted to the numerical simulation of wave breaking. It presents the results of a numerical workshop that was held during the conference LOMA04. The objective is to compare several mathematical models (compressible or incompressible) and associated numerical methods to compute the flow field during a wave breaking over a reef. The methods will also be compared with experiments.

This paper is devoted to the numerical simulation of wave
breaking. It presents the results of a numerical workshop that was
held during the conference LOMA04. The objective is to compare
several mathematical models (compressible or incompressible) and
associated numerical methods to compute the flow field during a
wave breaking over a reef. The methods will also be compared with
experiments.