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|Auteur||Lani, Andrea (firstname.lastname@example.org)|
|Titre||An Object Oriented and High Performance Platform for Aerothermodynamics Simulation|
|Département||F511 - Faculté des sciences appliquées - Mécanique (email@example.com)|
|Intitulé du diplôme||Doctorat en Sciences de l'ingénieur|
|Date de défense||2008-12-04|
Formaggia, Luca (Membre du jury/Committee Member)
Gaspart, Pierre (Membre du jury/Committee Member)
Gicquel, Olivier (Membre du jury/Committee Member)
Schwane, Richard (Membre du jury/Committee Member)
Degrez, Gérard (Président du jury/Committee Chair)
Deconinck, Herman (Promoteur/Director)
|Mots-clés||finite volume, aerothermodynamics, residual distribution, object oriented, COOLFLUID, unstructured, high performance, nonequilibrium|
|Résumé||This thesis presents the author's contribution
to the design and implementation of COOLFluiD,
an object oriented software platform for
the high performance simulation of multi-physics phenomena on unstructured grids. In this context, the final goal has been to provide a reliable tool for handling high speed aerothermodynamic
applications. To this end, we introduce a number of design techniques that have been developed in order to provide the framework with flexibility
and reusability, allowing developers to easily integrate new functionalities such as arbitrary mesh-based data structures, numerical algorithms (space discretizations, time stepping schemes, linear system solvers, ...),and physical models.
Furthermore, we describe the parallel algorithms
that we have implemented in order to efficiently
read/write generic computational meshes involving
millions of degrees of freedom and partition them
in a scalable way: benchmarks on HPC clusters with
up to 512 processors show their effective suitability for large scale computing.
Several systems of partial differential equations,
characterizing flows in conditions of thermal and
chemical equilibrium (with fixed and variable elemental fractions)and, particularly, nonequilibrium (multi-temperature models)
have been integrated in the framework.
In order to simulate such flows, we have developed
two state-of-the-art flow solvers:
1- a parallel implicit 2D/3D steady and unsteady cell-centered Finite Volume (FV) solver for arbitrary systems of PDE's on hybrid unstructured meshes;
2- a parallel implicit 2D/3D steady vertex-centered Residual Distribution (RD) solver for arbitrary systems of PDE's on meshes with simplex elements (triangles and tetrahedra).
The FV~code has been extended to handle all
the available physical models, in regimes ranging from incompressible to hypersonic.
As far as the RD code is concerned, the strictly conservative variant of the RD method, denominated CRD, has been applied for the first time in literature to solve high speed viscous flows in thermochemical nonequilibrium, yielding some preliminary outstanding results on a challenging double cone flow simulation.
All the developments have been validated on real-life testcases of current interest in the aerospace community. A quantitative comparison with experimental measurements and/or literature has been performed whenever possible.