Study for the validation of Code Saturne for turbulent flow simulations

Cita com:
hdl:2117/106220
Document typeBachelor thesis
Date2017-06
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Abstract
Nowadays, turbulent flows are of great interest in many applications because they mix
fluid much more effectively than a comparable laminar flow due to its diffusivity. The
conservation of the properties of the Navier-Stokes equations is of extremely importance
for an accurate description of turbulent flows. This thesis analyzes the behavior of
Code_Saturne, a multipurpose open-source CFD software package that is included in
the Partnership for Advanced Computing in Europe (PRACE), in terms of kinetic energy
conservation in turbulent flows. In order to do so, Code_Saturne is compared with a selfmade
spectro-consistent 2D code and another spectro-consistent 3D code that exactly
preserve the symmetries of the underlying differential operators of the Navier-Stokes
equations, i.e. the convective operator is approximated by a skew-symmetric matrix
and the diffusive operator by a symmetric, positive-definite matrix.
The well known benchmark cases of the 2D Taylor vortex and the 3D Taylor-Green vortex
are solved. A sensitivity analysis is performed in order to assess the best parameters
of Code_Saturne that yield the best performance for both structured and unstructured
meshes. The results show that Code_Saturne strictly conserves kinetic energy on regular
Cartesian grids if an appropriate fully centered scheme is used together with the
deactivation of the Rhie Chow interpolation. On 3D grids, the fully turbulent flow reveals
that the presence of three dimensional effects due to vortex stretching causes
a numerical dissipation that can be overcomed by refining the mesh size. However,
this formulation does not allow to strictly preserve kinetic energy on unstructured grids
due to the instabilities generated on the pressure gradient term. Finally, a set of configuration
parameters that follow the aforementioned properties for Code_Saturne are
provided.
Description
Introduction. Code_Saturne is a multipurpose Computational Fluid Dynamics (CFD) software package, which has been developed by EDF (France). Code_Saturne's open-source status allows for answers to specific needs that cannot easily be made available in commercial "black box" packages. It is also one of the 12 solvers selected by the Unified European Application Benchmark Suite (UEABS) inside PRACE and has been thoroughly proved to scale on large systems.Goal.The goal of this project is to use high performance computing to assess how Code_Saturne is able to characterize and solve turbulent flows, using the Taylor-Green vortex as a benchmark problem.
SubjectsComputational fluid dynamics, Turbulence--Simulation methods, Dinàmica de fluids computacional, Turbulència -- Simulació numèrica
DegreeGRAU EN ENGINYERIA EN TECNOLOGIES AEROESPACIALS (Pla 2010)
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ANNEX_242.pdf | 618,3Kb | View/Open | ||
BUDGET_374.pdf | 432,7Kb | View/Open |