Application of an explicit algebraic Reynolds stress model within a hybrid LES-RANS method
Publication date
2008
Document type
Research article
Author
Jaffrézic, Benoit
Organisational unit
Scopus ID
ISSN
Series or journal
Flow, turbulence and combustion : an international journal published in association with ERCOFTAC
Periodical volume
81
Periodical issue
3
First page
415
Last page
448
Peer-reviewed
✅
Part of the university bibliography
✅
Abstract
Large-eddy simulations (LES) still suffer from extremely large resources required for the resolution of the near-wall region, especially for high-Re flows. That is the main motivation for setting up hybrid LES-RANS methods. Meanwhile a variety of different hybrid concepts were proposed mostly relying on linear eddy-viscosity models. In the present study a hybrid approach based on an explicit algebraic Reynolds stress model (EARSM) is suggested. The model is applied in the RANS mode with the aim of accounting for the Reynolds stress anisotropy emerging especially in the near-wall region. For the implementation into a CFD code this anisotropy-resolving closure can be formally expressed in terms of a non-linear eddy-viscosity model (NLEVM). Its extra computational effort is small, still requiring solely the solution of one additional transport equation for the turbulent kinetic energy. In addition to this EARSM approach, a linear eddy-viscosity model (LEVM) is used in order to verify and emphasize the advantages of the non-linear model. In the present formulation the predefinition of RANS and LES regions is avoided and a gradual transition between both methods is assured. A dynamic interface criterion is suggested which relies on the modeled turbulent kinetic energy and the wall distance and thus automatically accounts for the characteristic properties of the flow. Furthermore, an enhanced version guaranteeing a sharp interface is proposed. The interface behavior is thoroughly investigated and it is shown how the method reacts on dynamic variations of the flow field. Both model variants, i.e. LEVM and EARSM, have been tested on the basis of the standard plane channel flow and even more detailed on the flow over a periodic arrangement of hills using fine and coarse grids. © 2008 Springer Science+Business Media B.V.
Cite as
In: Flow, turbulence and combustion / Europäische Kommission / European Research Community on Flow, Turbulence and Combustion. - Dordrecht [u.a.] : Springer Science + Business Media B.V., 1947- ; ZDB-ID: 1492282-4 . - Bd. 81.2008, 3, Seite 415-448
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