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

Jaffrézic, B.; Breuer, M.

doi:10.1007/s10494-008-9146-2

Cited by 24 publications

(11 citation statements)

References 54 publications

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“…In order to better account for the anisotropy emerging especially in the near-wall region, in [11] the description of the nearwall region was enhanced by the introduction of the explicit algebraic Reynolds stress model (EARSM) proposed by Wallin and Johansson [12]. It represents a compromise between the too expensive full RSMs and classical linear eddy-viscosity models based on the Boussinesq approximation not capable to account for the stress anisotropy.…”

Section: Unified Les-urans Methodology With Soft Interfacementioning

confidence: 99%

“…If this quantity is below a user-defined value, the method works in URANS mode, otherwise the LES mode is applied. The influence of the location of the interface on the outcome of the hybrid predictions was studied in detail [9,11,14]. It was found that the results are not strongly depending on the chosen location as long as it is positioned in the log-layer region.…”

Section: Unified Les-urans Methodology With Soft Interfacementioning

confidence: 99%

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Hybrid LES‐RANS Modeling of Complex Turbulent Flows

Breuer

Schmidt

2014

Proc Appl Math and Mech

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The paper describes a state-of-the-art hybrid LES-URANS method for the simulation of complex internal and external turbulent flows. Relying on a unified LES-URANS approach with a soft interface the methodology is designed for wall-bounded non-equilibrium flows. The unsteady Reynolds-averaged Navier-Stokes (URANS) mode within the hybrid approach is taken into account by an explicit algebraic Reynolds stress model (EARSM), which guarantees an appropriate representation of the anisotropic near-wall turbulence. All non-closed terms in the transport equation of the turbulent kinetic energy are modeled by enhanced formulations using the EARSM (production and diffusion term) and the splitting of the dissipation rate into a homogeneous and an inhomogeneous contribution. The former is expressed analytically by a Taylor series expansion of the homogeneous lateral Taylor microscale in the vicinity of the wall guaranteeing the correct asymptotic behavior. The latter is incorporated into the diffusion term. The interface location between the large-eddy simulation (LES) mode and the URANS mode is determined automatically on-the-fly based on the modeled turbulent kinetic energy and the distance to the wall. For transitional (external) flows an additional dynamic transition criterion is applied which determines the laminar and the turbulent flow regimes and is combined with the existing interface criterion. An internal flow over a periodic arrangement of hills and an external flow past a SD7003 airfoil with a laminar separation bubble are taken into account for a detailed evaluation of the method.

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Section: Unified Les-urans Methodology With Soft Interfacementioning

confidence: 99%

Section: Unified Les-urans Methodology With Soft Interfacementioning

confidence: 99%

Hybrid LES‐RANS Modeling of Complex Turbulent Flows

Breuer

Schmidt

2014

Proc Appl Math and Mech

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“…One of the first studies comparing the performance of linear and non-linear hybrid models for the periodic hills was performed by Jaffrézic and Breuer [36]. No significant differences between the linear and non-linear hybrid models were observed for the grids tested.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the sensitivity of turbulent closures and coupling of hybrid RANS‐LES models for predicting flow fields with separation and reattachment

Kumar

Lakshmanan

Gopalan

et al. 2016

Numerical Methods in Fluids

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Summary Hybrid models have found widespread applications for simulation of wall‐bounded flows at high Reynolds numbers. Typically, these models employ Reynolds‐averaged Navier–Stokes (RANS) and large eddy simulation (LES) in the near‐body and off‐body regions, respectively. A number of coupling strategies between the RANS and LES regions have been proposed, tested, and applied in the literature with varying degree of success. Linear eddy‐viscosity models (LEVM) are often used for the closure of turbulent stress tensor in RANS and LES regions. LEVM incorrectly predicts the anisotropy of Reynolds normal stress at the RANS‐LES interface region. To overcome this issue, use of non‐linear eddy‐viscosity models (NLEVM) have started receiving attention. In this study, a generic non‐linear blended modeling framework for performing hybrid simulations is proposed. Flow over the periodic hills is used as the test case for model evaluation. This case is chosen due to complex flow physics with simplified geometry. Analysis of the simulations suggests that the non‐linear hybrid models show a better performance than linear hybrid models. It is also observed that the non‐linear closures are less sensitive to the RANS‐LES coupling and grid resolution. Copyright © 2016 John Wiley & Sons, Ltd.

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“…Some researchers used two-equation models in RANS regions such as k − ε or k − ω in order to construct the hybrid RANS/LES model (Dejoan & Schiestel, 2001;Menter, Kuntz, & Langtry, 2003). An explicit algebraic Reynolds stress model was employed in the RANS region in Jaffrezic and Breuer (2008). The second aspect concerns how the LES-RANS interface is defined.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of near-wall solution approaches for large-eddy simulations of flow in a centrifugal pump impeller

Yao

Yang²,

Wang

2016

Engineering Applications of Computational Fluid Mechanics

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The turbulent flow in a centrifugal pump impeller is bounded by complex surfaces, including blades, a hub and a shroud. The primary challenge of the flow simulation arises from the generation of a boundary layer between the surface of the impeller and the moving fluid. The principal objective is to evaluate the near-wall solution approaches that are typically used to deal with the flow in the boundary layer for the large-eddy simulation (LES) of a centrifugal pump impeller. Three nearwall solution approaches -the wall-function approach, the wall-resolved approach and the hybrid Reynolds averaged Navier-Stoke (RANS) and LES approach -are tested. The simulation results are compared with experimental results conducted through particle imaging velocimetry (PIV) and laser Doppler velocimetry (LDV). It is found that the wall-function approach is more sparing of computational resources, while the other two approaches have the important advantage of providing highly accurate boundary layer flow prediction. The hybrid RANS/LES approach is suitable for predicting steady-flow features, such as time-averaged velocities and hydraulic losses. Despite the fact that the wall-resolved approach is expensive in terms of computing resources, it exhibits a strong ability to capture a small-scale vortex and predict instantaneous velocity in the near-wall region in the impeller. The wall-resolved approach is thus recommended for the transient simulation of flows in centrifugal pump impellers. ARTICLE HISTORY

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

Cited by 24 publications

References 54 publications

Hybrid LES‐RANS Modeling of Complex Turbulent Flows

Hybrid LES‐RANS Modeling of Complex Turbulent Flows

Investigation of the sensitivity of turbulent closures and coupling of hybrid RANS‐LES models for predicting flow fields with separation and reattachment

Evaluation of near-wall solution approaches for large-eddy simulations of flow in a centrifugal pump impeller

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