Éditeur(s) : HAL CCSD EDP Sciences
Résumé : International audience
We show first results of 3D simulation of sea currents in a realistic context. We use the full Navier-Stokes equations for incompressible viscous fluid. The problem is solved using a second order incremental projection method associated with the finite volume of the staggered (MAC) scheme for the spatial discretization. After validation on classical cases, it is used in a numerical simulation of the Pointe à Pitre harbour area. The use of the fictious domain method permits us to take into account the complexity of bathymetric data and allows us to work with regular meshes and thus preserves the efficiency essential for a 3D code.
ISSN: 1270-900X
Guidel, France

hal-00728894
https://hal.archives-ouvertes.fr/hal-00728894
DOI : 10.1051/proc/201235025

Éditeur(s) : HAL CCSD
Résumé : International audience
Récentes avancées sur le probleme de Helmholtz
Pointe-à-Pitre, Guadeloupe

hal-00771459
https://hal.univ-antilles.fr/hal-00771459

Éditeur(s) : HAL CCSD Society for Industrial and Applied Mathematics
Résumé : International audience
In this paper, we developed a theoretical study for nonconservative sytems in one dimension in order to construct numerical schemes for solving the Riemann problem. The nonconservative form of our model system required the use of a well-adapted theory in order to give us a sense of our problem. We chose a framework of generalized functions for solving a scalar hyperbolic equation with a discontinuous coefficient $sigma_t +usigma_x approx 0$, where u is the velocity solution of a Burgers's equation. After an explicit solution of the Riemann problem, we derived Godunov split schemes for computing an approximate solution of the Cauchy problem. We applied our study to a system modeling elasticity and a system modeling gas dynamics. Some stability properties of a scheme and its convergence to a generalized solution are proved for the first model. Numerical experiments confirmed this convergence result. For the second model, calculations of flows containing weak-to-moderate shocks showed that conservation errors are reduced when the mesh is refined but were not entirely eliminated.
ISSN: 0036-1429

hal-00770266
https://hal.univ-antilles.fr/hal-00770266
DOI : 10.1137/S0036142900378637

Éditeur(s) : HAL CCSD
Résumé : International audience
CMAIA 2006, a Conference on Mathematics and its Applications
St Augustine, Trinidad and Tobago

hal-00770273
https://hal.univ-antilles.fr/hal-00770273

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This article is devoted to the presentation of a multilevel method using finite differences that is well adapted for solving Stokes and Navier-Stokes problems in primitive variables. We use Uzawa type algorithms to solve the saddle point problems arising from spatial discretization by staggered grids and a semi-explicit temporal scheme. By means of a new change of basis operator, the two-dimensional velocity and pressure fields of an M.A.C mesh are gathered in a hierarchical order, into several grids preserving the M.A.C property on each of them. These new hierarchical unknowns, called Staggered Incremental Unknowns (SIU), allow us to develop techniques which reduce the cost of the resolution of either Stokes or generalized Stokes problems. An experimental estimation of the condition number of the inner matrix is given, and justifies the preconditioning effect of the staggered incremental unknowns.
ISSN: 0168-9274

hal-00770268
https://hal.univ-antilles.fr/hal-00770268
DOI : 10.1016/S0168-9274(99)00044-6

Éditeur(s) : HAL CCSD
Résumé : International audience
Proceedings of the PRISM'97
Nijmegen, Netherlands

hal-00770278
https://hal.univ-antilles.fr/hal-00770278

Éditeur(s) : HAL CCSD
Résumé : International audience
The calculation of Fock-Exchange integral is becoming an important computational challenge in solving the quantum properties of systems with many electrons. In this work we show how techniques that are used in electromagnetic simulations for the similar Poisson equation can help in accelerating the calculation of such exchange integrals. The approach we present can be especially efficient for quasi-planar systems such as Graphene nano-ribbons (GNRs) or elongated systems such as carbon nano-tubes (CNTS) and the 1D Carbyne.
16th International Conference on Electromagnetics in Advanced Applications, ICEAA 2014
Palm Beach, Aruba

hal-01398279
https://hal.archives-ouvertes.fr/hal-01398279

Éditeur(s) : HAL CCSD
Résumé : International audience
9th Meeting of the Caribbean Academy of Science
Pointe-à-Pitre, Guadeloupe

hal-00778160
https://hal.univ-antilles.fr/hal-00778160

Éditeur(s) : HAL CCSD
Résumé : International audience
We show first results of 3D simulation of sea currents in a realistic context. We use the full Navier-Stokes equations for incompressible viscous fluid. The problem is solved using a second order incremental projection method associated with the finite volume of the staggered (MAC) scheme for the spatial discretization. After validation on classical cases, it is used in a numerical simulation of the Pointe à Pitre harbour area. The use of the fictious domain method permits us to take into account the complexity of bathymetric data and allows us to work with regular meshes and thus preserves the efficiency essential for a 3D code.
ESAIM : Proceedings
Guidel, France

hal-00770270
https://hal.univ-antilles.fr/hal-00770270
DOI : 10.1051/proc/201235025

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
ISSN: 0749-159X

hal-00530821
https://hal.archives-ouvertes.fr/hal-00530821

Éditeur(s) : HAL CCSD
Résumé : International audience
17th International Conference on Electromagnetic in Advanced Applications, ICEAA2015
Torino, Italy

hal-01398274
https://hal.archives-ouvertes.fr/hal-01398274

Éditeur(s) : HAL CCSD
Résumé : International audience
The solution of the Poisson equation is an essential stage in the calculation of quantum properties of materials as it appears both in the electrostatic Hartree term and in the Fock exchange operator. We discuss here an integral method for the calculation of Poisson potential and demonstrate its integration with a Density Functional Theory (DFT) code. We show some results on elongated carbon chains.
2015 International Conference on Electromagnetics in Advanced Applications, ICEAA 2015
Torino, Italy

hal-01398278
https://hal.archives-ouvertes.fr/hal-01398278

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
We mainly study a system of two coupled nonlinear Schrödinger equations where one equation includes gain and the other one includes losses. This model constitutes a generalization of the model of pulse propagation in bire-fringent optical fibers. We answered partially to a question of some authors in [8], that in the Manakov case, the solution stays in L 2 (0, T ; H 1), that means that the solution can not blow up in finite time. More precisely, the bound that is provided in this paper does not seem to be optimal but different than those that has been given from a previous study [8]. Thanks to the way we treat the a priori estimate, we obtain a sharp bound in L 2 (0, T ; H 1), which would be difficult to reach from the study of other authors [8]. The result is illustrated by numerical results which have been obtained with a finite element solver well adapted for that purpose.
ISSN: 0022-2526

Droits : http://creativecommons.org/licenses/by/
hal-01270459
https://hal.archives-ouvertes.fr/hal-01270459
https://hal.archives-ouvertes.fr/hal-01270459/document
https://hal.archives-ouvertes.fr/hal-01270459/file/paperver2.pdf

Éditeur(s) : HAL CCSD
Résumé : Emory University
International audience
Preconditionning Techniques for Large Sparse Matrix problems in Science and Industrial applications
Atlanta, United States

hal-00778154
https://hal.univ-antilles.fr/hal-00778154

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 0885-7474

hal-00601484
https://hal.archives-ouvertes.fr/hal-00601484
DOI : 10.1007/s10915-011-9480-8

Éditeur(s) : HAL CCSD
Résumé : International audience
15th Meeting of the Caribbean Academy of Science
Gosier, Guadeloupe

hal-00778158
https://hal.univ-antilles.fr/hal-00778158

Éditeur(s) : HAL CCSD
Résumé : International audience
International Meeting on Grid and Parallel Computing
Beyrouth, Lebanon

hal-00770281
https://hal.univ-antilles.fr/hal-00770281

Éditeur(s) : HAL CCSD
Multilevel tools for problems from Physics
Pointe-à-Pitre, Guadeloupe

hal-00771421
https://hal.univ-antilles.fr/hal-00771421

Éditeur(s) : HAL CCSD
Résumé : International audience
International Journal of Numerical Analysis & Modeling (IJNAM)

hal-00601461
https://hal.archives-ouvertes.fr/hal-00601461