Towards Hybrid LES-RANS-Coupling for Complex Flows with Separation

Jaffrézic, B.; Breuer, M.; Chikhaoui, Oussama; Deng, Ganbo; Visonneau, Michel

doi:10.1051/proc:2007010

Cited by 6 publications

(6 citation statements)

References 16 publications

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“…1. A detailed evaluation of this hybrid approach can be found in [11]. Almost excellent predictions of the mean streamwise velocity profiles obtained by LES employing the standard SM are evident.…”

Section: Influence Of the Turbulence Modeling Strategymentioning

confidence: 94%

“…This method employs a one-equation (OE) model based on the transport equation for the turbulent kinetic energy which governs the modeled turbulent kinetic energy k mod in RANS mode and the subgrid scale turbulent kinetic energy k sgs in LES mode. More details about the method and switching criteria defining the LES-RANS interface can be found in [5,11]. A summary of the simulations performed is given in Table 1 displaying the notation used henceforth, the main parameters and information pertinent to the computations, and the location of separation and reattachment…”

Section: Computational Detailsmentioning

confidence: 99%

“…The flow over a periodic arrangement of smoothly contoured hills [16] has been extensively studied over the past few years [4][5][6]9,11,12,14]. Recently, this flow configuration at Re b = 10, 595 was selected as a common test case within the French-German research group on 'Large-Eddy Simulation of Complex Flows'.…”

Section: Introductionmentioning

confidence: 99%

“…As reference data serve results from a highly resolved LES obtained with roughly 13 million cells [6]. The performance of the DES is further evaluated by comparison of its results to those computed on the same grid using LES with the standard and the dynamic Smagorinsky models and an alternative hybrid LES-RANS proposed by Breuer and Jaffrézic [5] and Jaffrézic et al [11]. In addition, LES data employing an immersed boundary technique on Cartesian meshes are included.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Detached Eddy Simulations for predicting the flow over periodic hills

Saric¹,

Jakirlić²,

Breuer³

et al. 2007

ESAIM: Proc.

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The performance of an hybrid LES-RANS strategy, the Detached Eddy Simulation (DES), as a predictive tool for turbulent channel flow with massive separation is scrutinized. This is undertaken in a collaborative effort involving five different flow solvers used by five different groups to cover a broad range of numerical methods and implementations. This paper concentrates on DES results obtained with a computational mesh of approximately one million cells. The results are compared to those obtained by Large Eddy Simulations (LES) using the standard and the dynamic Smagorinsky models and an alternative hybrid LES-RANS -all computed on the same grid. Data of a highly resolved LES (roughly 13 million cells) are used for reference. Furthermore, the impact of resolution and, therefore, the location of the LES-RANS interface is studied.

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Section: Influence Of the Turbulence Modeling Strategymentioning

confidence: 94%

Section: Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of Detached Eddy Simulations for predicting the flow over periodic hills

Saric¹,

Jakirlić²,

Breuer³

et al. 2007

ESAIM: Proc.

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“…Thus, it is obvious that the instantaneous k mod fluctuates around the curve k crit , which creates these mixed LES-RANS zones or RANS islands. Therefore, two additional criteria based on y * have been tested (see Breuer et al [11] and Jaffrézic et al [25]). In the present paper only one of them is applied.…”

Section: Les-rans Interfacementioning

confidence: 99%

Application of an Explicit Algebraic Reynolds Stress Model within a Hybrid LES–RANS Method

Jaffrézic

Breuer

2008

Flow Turbulence Combust

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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 eddyviscosity 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 eddyviscosity 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 416 Flow Turbulence Combust (2008) 81:415-448 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.Keywords Hybrid LES-RANS · EARSM · Interface and interface criteria · Modeled and resolved scales

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Turbulent Flow Separation Control by Boundary-Layer Forcing: A Computational Study

Saric

Jakirlić

Tropea

2006

New Results in Numerical and Experimental Fluid Mechanics V

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Towards Hybrid LES-RANS-Coupling for Complex Flows with Separation

Cited by 6 publications

References 16 publications

Evaluation of Detached Eddy Simulations for predicting the flow over periodic hills

Evaluation of Detached Eddy Simulations for predicting the flow over periodic hills

Application of an Explicit Algebraic Reynolds Stress Model within a Hybrid LES–RANS Method

Turbulent Flow Separation Control by Boundary-Layer Forcing: A Computational Study

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