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Journal ArticleDOI

An explicit algebraic Reynolds stress model for incompressible and compressible turbulent flows

25 Jan 2000-Journal of Fluid Mechanics (Cambridge University Press)-Vol. 403, Iss: 1, pp 89-132
TL;DR: In this article, an explicit algebraic Reynolds stress turbulence model (EARSM) is presented for both incompressible and compressible three-dimensional wall-bounded turbulent flows, which represents a solution of implicit ARSM equations, where the production to dissipation ratio is obtained as a solution to a nonlinear algebraic relation.
Abstract: Some new developments of explicit algebraic Reynolds stress turbulence models (EARSM) are presented. The new developments include a new near-wall treatment ensuring realizability for the individual stress components, a formulation for compressible flows, and a suggestion for a possible approximation of diffusion terms in the anisotropy transport equation. Recent developments in this area are assessed and collected into a model for both incompressible and compressible three-dimensional wall-bounded turbulent flows. This model represents a solution of the implicit ARSM equations, where the production to dissipation ratio is obtained as a solution to a nonlinear algebraic relation. Three-dimensionality is fully accounted for in the mean flow description of the stress anisotropy. The resulting EARSM has been found to be well suited to integration to the wall and all individual Reynolds stresses can be well predicted by introducing wall damping functions derived from the van Driest damping function. The platform for the model consists of the transport equations for the kinetic energy and an auxiliary quantity. The proposed model can be used with any such platform, and examples are shown for two different choices of the auxiliary quantity.
Citations
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Journal ArticleDOI
TL;DR: This paper presents a method of using deep neural networks to learn a model for the Reynolds stress anisotropy tensor from high-fidelity simulation data and proposes a novel neural network architecture which uses a multiplicative layer with an invariant tensor basis to embed Galilean invariance into the predicted anisotropic tensor.
Abstract: There exists significant demand for improved Reynolds-averaged Navier–Stokes (RANS) turbulence models that are informed by and can represent a richer set of turbulence physics. This paper presents a method of using deep neural networks to learn a model for the Reynolds stress anisotropy tensor from high-fidelity simulation data. A novel neural network architecture is proposed which uses a multiplicative layer with an invariant tensor basis to embed Galilean invariance into the predicted anisotropy tensor. It is demonstrated that this neural network architecture provides improved prediction accuracy compared with a generic neural network architecture that does not embed this invariance property. The Reynolds stress anisotropy predictions of this invariant neural network are propagated through to the velocity field for two test cases. For both test cases, significant improvement versus baseline RANS linear eddy viscosity and nonlinear eddy viscosity models is demonstrated.

1,159 citations


Cites background from "An explicit algebraic Reynolds stre..."

  • ...More advanced nonlinear eddy viscosity models have also been proposed (Pope 1975; Craft et al. 1996; Wallin & Johansson 2000) which rely on higher-order products of the mean strain rate and rotation rate tensors....

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Journal ArticleDOI
Florian R. Menter1, Yury Egorov1
TL;DR: The article gives an overview of the Scale-Adaptive Simulation (SAS) method and the motivation for the formulation of the SAS method is given and a detailed explanation of the underlying ideas is presented.
Abstract: The article gives an overview of the Scale-Adaptive Simulation (SAS) method developed by the authors during the last years. The motivation for the formulation of the SAS method is given and a detailed explanation of the underlying ideas is presented. The derivation of the high-Reynolds number form of the equations as well as the calibration of the constants is provided. The concept of SAS is explained using several generic examples and test cases. In a companion article, the model is applied to more complex industrial-type applications.

724 citations

Journal ArticleDOI
16 Mar 2017
TL;DR: In this paper, a physics-informed machine learning framework is proposed to improve the predictive capabilities of RANS models by leveraging existing direct numerical simulations databases, and the discrepancies in Reynolds-averaged Navier-Stokes (RANS) modeled Reynolds stresses can be explained by mean flow features.
Abstract: We show that the discrepancies in Reynolds-averaged Navier-Stokes (RANS) modeled Reynolds stresses can be explained by mean flow features. A physics-informed machine learning framework is proposed to improve the predictive capabilities of RANS models by leveraging existing direct numerical simulations databases.

495 citations

Journal ArticleDOI
TL;DR: The Onera elsA CFD software is both a software package capitalizing the innovative results of research over time and a multi-purpose tool for applied CFD and multi-physics.
Abstract: The Onera elsA CFD software is both a software package capitalizing the innovative results of research over time and a multi-purpose tool for applied CFD and multi-physics. The research input from Onera and other laboratories and the feedback from aeronautical industry users allow enhancement of its capabilities and continuous improvement. The paper presents recent accomplishments of varying complexity from research and industry for a wide range of aerospace applications: aircraft, helicopters, turbomachinery...

380 citations

Journal ArticleDOI
TL;DR: A review of the problems and successes of computing turbulent flow can be found in this paper, where the authors provide the interested reader with most of the appropriate sources of turbulence modelling, exhibiting either as much detail as it is possible, by means of bibliography, or illustrating some of the most recent developments on the numerical modelling of turbulent flows.

357 citations

References
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Journal ArticleDOI
TL;DR: In this paper, two new two-equation eddy-viscosity turbulence models are presented, which combine different elements of existing models that are considered superior to their alternatives.
Abstract: Two new two-equation eddy-viscosity turbulence models will be presented. They combine different elements of existing models that are considered superior to their alternatives. The first model, referred to as the baseline (BSL) model, utilizes the original k-ω model of Wilcox in the inner region of the boundary layer and switches to the standard k-e model in the outer region and in free shear flows. It has a performance similar to the Wilcox model, but avoids that model's strong freestream sensitivity

15,459 citations


"An explicit algebraic Reynolds stre..." refers background in this paper

  • ...For a more thorough comparison between K–ε and K–ω models the reader may wish to consult Menter (1994)....

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Book
01 Jan 1993
TL;DR: In this paper, the authors proposed a compressible ecoulement for compressible ECCs, based on the disquette reference record created on 2005-11-18, modified on 2016-08-08.
Abstract: Keywords: ecoulement : compressible Note: + disquette Reference Record created on 2005-11-18, modified on 2016-08-08

7,023 citations


Additional excerpts

  • ...Other possibilities than y+ are Rey ≡ √ Ky/ν or the turbulent Reynolds number Ret ≡ K2/νε (see e.g. Wilcox 1993)....

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Journal ArticleDOI
TL;DR: In this article, the authors developed a model of turbulence in which the Reynolds stresses are determined from the solution of transport equations for these variables and for the turbulence energy dissipation rate E. Particular attention is given to the approximation of the pressure-strain correlations; the forms adopted appear to give reasonably satisfactory partitioning of the stresses both near walls and in free shear flows.
Abstract: The paper develops proposals for a model of turbulence in which the Reynolds stresses are determined from the solution of transport equations for these variables and for the turbulence energy dissipation rate E. Particular attention is given to the approximation of the pressure-strain correlations; the forms adopted appear to give reasonably satisfactory partitioning of the stresses both near walls and in free shear flows. Numerical solutions of the model equations are presented for a selection of strained homogeneous shear flows and for two-dimensional inhomogeneous shear flows including the jet, the wake, the mixing layer and plane channel flow. In addition, it is shown that the closure does predict a very strong influence of secondary strain terms for flow over curved surfaces.

3,855 citations


"An explicit algebraic Reynolds stre..." refers background or methods or result in this paper

  • ...4 by Launder et al. (1975), but more recent studies have suggested a higher value close to 5 9 , see e.g. Lumley (1978) and Shabbir & Shih (1992). This means that the last term in equation (1.13) is of quite small influence, also noticed by Taulbee (1992). Setting c2 = 5 9 one obtains the simplified but still implicit equation ( c1 − 1 + P ε ) a = − 8 15 S + 4 9 (aΩ−Ωa) ....

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  • ...Moreover, the Launder et al. (1975) model gives quite poor predictions of this case when used in a differential form. The very good predictions of the present EARSM can thus be regarded as a bit fortuitous. Nevertheless, the self-consistent approach gives a model with the correct asymptotic behaviour, which is a pre-requisite for reasonable predictions in the limit of high shear. It is important to make clear that the proposed model is not intended for these extreme high shear rates and the normal stress components are not as well predicted as the turbulent kinetic energy. It is, however, an important step towards a more general engineering model that the model is able to give reasonable results in extreme flow cases also. In flows with an adverse pressure gradient, the production to dissipation ratio is greater than 1 and eddy-viscosity models with constant Cμ overestimate the turbulent viscosity or the a12 anisotropy. Bradshaw’s assumption, which is adopted by Menter (1993) in the shear stress transport (SST) model, forces the a12 anisotropy to be constant for P/ε ratios greater than unity, which gives β1 ∼ 1/σ....

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  • ...The value of c2 in the rapid pressure–strain model was originally suggested to be 0.4 by Launder et al. (1975), but more recent studies have suggested a higher value close to 5 9 , see e.g. Lumley (1978) and Shabbir & Shih (1992)....

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  • ...The Taulbee (1992) model could, however, be directly compared to the implicit ARSM since the basic approach is the Launder et al. (1975) model with similar choices of the model coefficients....

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  • ...Solution of the general quasi-linear ARSM equation So far, the explicit solution of the ARSM resulting from the special case of the Launder et al. (1975) model with c2 = 5 9 has been analysed....

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Journal ArticleDOI
TL;DR: In this paper, a two-equation turbulence model is proposed that is shown to be quite accurate for attached boundary layers in adverse pressure gradient, compressible boundary layers, and free shear flows.
Abstract: A comprehensive and critical review of closure approximations for two-equation turbulence models has been made. Particular attention has focused on the scale-determining equation in an attempt to find the optimum choice of dependent variable and closure approximations. Using a combination of singular perturbation methods and numerical computations, this paper demonstrates that: 1) conventional A:-e and A>w formulations generally are inaccurate for boundary layers in adverse pressure gradient; 2) using "wall functions'' tends to mask the shortcomings of such models; and 3) a more suitable choice of dependent variables exists that is much more accurate for adverse pressure gradient. Based on the analysis, a two-equation turbulence model is postulated that is shown to be quite accurate for attached boundary layers in adverse pressure gradient, compressible boundary layers, and free shear flows. With no viscous damping of the model's closure coefficients and without the aid of wall functions, the model equations can be integrated through the viscous sublayer. Surface boundary conditions are presented that permit accurate predictions for flow over rough surfaces and for flows with surface mass addition.

2,783 citations


"An explicit algebraic Reynolds stre..." refers methods in this paper

  • ...For that choice, the standard Wilcox (1988) K–ω, also without damping functions, must be used as the platform....

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  • ...This case is computed using the standard Wilcox (1988) K–ω model and the EARSM based on that....

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  • ...Figure 21 shows the computational results for the two-dimensional RAE2822 aerofoil profile using the proposed EARSM compared to the Wilcox (1994) K–ω model. The flow in this case is compressible and the formulation is modified in a manner described in § 4. The EARSM approach clearly improves the position of the shock and the results are very much in line with differential Reynolds stress computations by Hellström, Davidson & Rizzi (1994) for exactly the same conditions and geometry. The damping function in the EARSM is formulated in terms of y as well as y∗ and the figure shows no major differences between these approaches except in the separated region where the y formulation gives a somewhat larger negative skin friction. In the figure a computation using the proposed EARSM without any damping functions whatsoever is also shown. For that choice, the standard Wilcox (1988) K–ω, also without damping functions, must be used as the platform....

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  • ...Figure 21 shows the computational results for the two-dimensional RAE2822 aerofoil profile using the proposed EARSM compared to the Wilcox (1994) K–ω model....

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  • ...Figure 21 shows the computational results for the two-dimensional RAE2822 aerofoil profile using the proposed EARSM compared to the Wilcox (1994) K–ω model. The flow in this case is compressible and the formulation is modified in a manner described in § 4. The EARSM approach clearly improves the position of the shock and the results are very much in line with differential Reynolds stress computations by Hellström, Davidson & Rizzi (1994) for exactly the same conditions and geometry....

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Proceedings ArticleDOI
06 Jul 1993
TL;DR: In this article, two versions of the k-w two-equation turbulence model are presented, the baseline model and the Shear-Stress Transport (SSn) model.
Abstract: Two new versions of the k - w two-equation turbulence model will be presented. The new Baseline (BSL) model is designed to give results similar to those of the original k - w model of Wilcox. but without its strong dependency on arbitrary freestream values. The BSL model is identical to the Wilcox model in the inner SOC7£; of the boundary-layer but changes gradually to the standard k - f. model (in a k - w fonnulation) towards the boundary-layer edge. The new model is also virtually identical to the k - f. model for free shear layers. The second version of the model is called Shear-Stress Transport (SSn model. It is a variation of the BSL model with the additional ability to account for the transport of the principal turbulent shear stress in adverse pressure gradient boundary-layers. The model is based on Bradshaw's assumption that the principal shear-stress is pro­ portional to the turbulent kinetic energy, which is introduced into the definition of the eddy-viscosity. Both models are tested for a large number of different fiowfields. The results of the BSL model are similar to those of the original k - w model, but without the undesirable free stream dependency. The predictions of the SST model are also independent of the freestrearn values but show better agreement with exper­ imental data for adverse pressure gradient boundary-layer flows.

2,470 citations


"An explicit algebraic Reynolds stre..." refers background or methods in this paper

  • ...This behaviour is not a natural part of eddy-viscosity based models, but was incorporated in a somewhat ad hoc manner by Menter (1993)....

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  • ...For a more thorough comparison between K–ε and K–ω models the reader may wish to consult Menter (1994). It is also interesting to note the clear improvement in the K-profiles with the proposed EARSM both for the K–ε and K–ω models in figure 14....

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  • ...Bradshaw’s assumption, which is adopted by Menter (1993) in the shear stress transport (SST) model, forces the a12 anisotropy to be constant for P/ε ratios greater than unity, which gives β1 ∼ 1/σ....

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  • ...The current model ( ) compared to the eddy-viscosity model ( ) and the Menter (1993) SST model ( )....

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  • ...The current model without ( ) and with ( ) diffusion model compared to an eddy-viscosity model ( ) and the Menter (1993) SST model ( )....

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