A Comparative Study of the Turbulent Flow Over a Periodic Arrangement of Smoothly Contoured Hills

Breuer, M.; Jaffrézic, B.; Peller, Nikolaus; Manhart, Michael; Fröhlich, Jochen; Hinterberger, Christof; Rodi, W.; Deng, Ganbo; Chikhaoui, Oussama; uSarić, Sanjin; Jakirlić, Suad

doi:10.1007/978-1-4020-5152-2_73

Cited by 12 publications

(20 citation statements)

References 6 publications

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“…suitable SGS models, wallfunctions, resolution requirements etc. Recent results on this test case are presented by Breuer et al [1], who compare data obtained from a number of different simulations, including various Reynolds numbers, resolutions and simulation approaches (LES, DNS).…”

Section: Introductionmentioning

confidence: 99%

Simulations of Turbulent Flow in a Plane Asymmetric Diffuser

Herbst

Schlatter

Henningson

2007

Flow Turbulence Combust

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Large-eddy simulations (LES) of a planar, asymmetric diffuser flow have been performed. The diverging angle of the inclined wall of the diffuser is chosen as 8.5 • , a case for which recent experimental data are available. Reasonable agreement between the LES and the experiments is obtained. The numerical method is further validated for diffuser flow with the diffuser wall inclined at a diverging angle of 10 • , which has served as a test case for a number of experimental as well as numerical studies in the literature (LES, RANS). For the present results, the subgrid-scale stresses have been closed using the dynamic Smagorinsky model. A resolution study has been performed, highlighting the disparity of the relevant temporal and spatial scales and thus the sensitivity of the simulation results to the specific numerical grids used. The effect of different Reynolds numbers of the inflowing, fully turbulent channel flow has been studied, in particular, Re b = 4,500, Re b = 9,000 and Re b = 20,000 with Re b being the Reynolds number based on the bulk velocity and channel half width. The results consistently show that by increasing the Reynolds number a clear trend towards a larger separated region is evident; at least for the studied, comparably low Reynolds-number regime. It is further shown that the small separated region occurring at the diffuser throat shows the opposite behaviour as the main separation region, i.e. the flow is separating less with higher Re b . Moreover, the influence of the Reynolds number on the internal layer occurring at the non-inclined wall described in a recent study has also been assessed. It can be concluded that this region close to the upper, straight wall, is more distinct for larger Re b . Additionally,

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Section: Introductionmentioning

confidence: 99%

Simulations of Turbulent Flow in a Plane Asymmetric Diffuser

Herbst

Schlatter

Henningson

2007

Flow Turbulence Combust

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“…For the sake of brevity two grids consisting of 160 × 100× 60 (grid A) and 80 × 100 × 30 (grid B) CVs in streamwise, wall-normal (res. : WR-LES wall-resolved LES [8,9,12]. Simulation type: Hybrid LES-RANS.…”

Section: Periodic Hill Flowmentioning

confidence: 99%

“…Since no DNS was performed at Re b = 10, 595 (based on the bulk velocity U b and the hill height h), the solution used for evaluating the hybrid simulations is a highly wall-resolved LES [8,9,12] consisting of a block-structured curvilinear grid with about 12.4 · 10 6 CVs using the finite-volume code LESOCC (Section 4). Some details about this solution denoted in the following WR-LES should be provided here.…”

Section: Periodic Hill Flowmentioning

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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“…Both codes were applied, LESOCC with the Smagorinsky model and ISIS with the WALE model [13,19]. Results and comparisons between both codes as well as additional validated codes concerning the hill flow test case in the LES context are available in [1,3]. We focus here on the comparison of DES simulations with the SA model.…”

Section: Des Simulations Including a Comparison Of Codesmentioning

confidence: 99%

“…The flow is assumed to be periodic in the streamwise direction. As no DNS was performed at the Reynolds number of Re b = 10, 595, the reference solution is a highly wall-resolved LES [1,7] consisting of a block-structured curvilinear grid with about 12.4 × 10 6 control volumes using the finite-volume code LESOCC (see Section 3.1). The grid points were clustered in the vicinity of the lower wall, the upper wall, and the region where the free shear layer appears.…”

Section: Periodic Hill Flowmentioning

confidence: 99%

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

et al. 2007

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Abstract. The paper is concerned with a new hybrid LES-RANS approach, which splits up the simulation into a near-wall RANS part and an outer LES part, both modes relying on a one-equation model for the turbulent kinetic energy. This model has been tested on the standard plane channel flow test case as well as on the flow over a periodic arrangement of hills. Encouraging results were achieved. In an additional study based on the detached-eddy simulation (DES) concept attempts have been made to improve the accuracy of the simulation by using adaptive local grid refinement. For this purpose, a criterion based on the residual of the budget of the mean momentum equations has been studied.

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A Comparative Study of the Turbulent Flow Over a Periodic Arrangement of Smoothly Contoured Hills

Cited by 12 publications

References 6 publications

Simulations of Turbulent Flow in a Plane Asymmetric Diffuser

Simulations of Turbulent Flow in a Plane Asymmetric Diffuser

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

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

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