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Development and validation of a LES methodology for complex wall-bounded flows : application to high-order structured and industrial unstructured solvers

Authors :
UCL - FSA/MECA - Département de mécanique
Winckelmans, Grégoire
Samin, Jean-Claude
Carati, Daniele
Dupret, François
Geuzaine, Philippe
Jeanmart, Hervé
Georges, Laurent
UCL - FSA/MECA - Département de mécanique
Winckelmans, Grégoire
Samin, Jean-Claude
Carati, Daniele
Dupret, François
Geuzaine, Philippe
Jeanmart, Hervé
Georges, Laurent
Publication Year :
2007

Abstract

Turbulent flows present structures with a wide range of scales. The computation of the complete physics of a turbulent flow (termed DNS) is very expensive and is, for the time being, limited to low and medium Reynolds number flows. As a way to capture high Reynolds number flows, a part of the physics complexity has to be modeled. Large eddy simulation (LES) is a simulation strategy where the large turbulent eddies present on a given mesh are captured and the influence of the non-resolved scales onto the resolved ones is modeled. The present thesis reports on the development and validation of a methodology in order to apply LES for complex wall-bounded flows. Discretization methods and LES models, termed subgrid scale models (SGS), compatible with such a geometrical complexity are discussed. It is proved that discrete a kinetic energy conserving discretization of the convective term is an attractive solution to perform stable simulations without the use of an artificial dissipation, as upwinding. The dissipative effect of the SGS model is thus unaffected by any additional dissipation process. The methodology is first applied to a developed parallel fourth-order incompressible flow solver for cartesian non-uniform meshes. In order to solve the resulting Poisson equation, an efficient multigrid solver is also developed. The code is first validated using DNS (Taylor-Green vortex, channel flow, four-vortex system) and LES (channel flow), and finally applied to the investigation of an aircraft two-vortex system in ground effect. The methodology is then applied to improve a RANS-based industrial unstructured compressible flow solver, developed at CENAERO, to perform well for LES applications. The proposed modifications are tested successfully on the unsteady flow past a sphere at Reynolds of 300 and 10000, corresponding to the subcritical regime.<br />(FSA 3)--UCL, 2007

Details

Database :
OAIster
Notes :
English
Publication Type :
Electronic Resource
Accession number :
edsoai.on1130587124
Document Type :
Electronic Resource