Non-Boussinesq subgrid-scale model with dynamic tensorial coefficients

Agrawal, Rahul; Whitmore, Michael P.; Griffin, Kevin P.; Bose, Sanjeeb; Moin, Parviz

doi:10.1103/physrevfluids.7.074602

Cited by 15 publications

(5 citation statements)

References 43 publications

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“…In particular, when we employ the scale-similarity model, the eddy-viscosity term is often employed to compensate for insufficient dissipation [23,24]. Furthermore, recent studies on anisotropic SGS modeling demonstrated that the employment of the additional stress that has no contribution to the energy transfer improves the prediction of the statistics in LES [4][5][6][7][8][9]. Therefore, we adopt the following decomposition of SGS stress by assuming that the eddy-viscosity term governs the energy transfer between GS and SGS [8,13]:…”

Section: A Decomposition Of Sgs Stressmentioning

confidence: 99%

“…Several studies addressed the development of non-eddy-viscosity or anisotropic SGS models and showed that these models improve the prediction of the statistics of turbulent flows [4][5][6][7][8][9][10][11]. Specifically, these anisotropic models provide a better prediction even in grid resolution cases that are coarser than in conventional eddy-viscosity models.…”

Section: Introductionmentioning

confidence: 99%

“…It is worth noting that some anisotropic models prohibit backward scatter, which is the local energy transfer from SGS to GS [4][5][6][7][8][9]. This indicates that additional stress, apart from energy transfer, can improve the performance of LES.…”

Section: Introductionmentioning

confidence: 99%

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Necessity of anisotropic subgrid-scale stress in coarse large-eddy simulation

Inagaki¹,

Kobayashi²

2023

Preprint

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This study discusses the necessity of anisotropic subgrid-scale (SGS) stress in large-eddy simulations (LESs) of turbulent shear flows using a coarse grid resolution. We decompose the SGS stress into two parts to observe the role of SGS stress in turbulent shear flows in addition to the energy transfer between grid-scale (GS or resolved scale) and SGS. One is the isotropic eddy-viscosity term, which contributes to energy transfer, and the other is the residual anisotropic term, which is separated from the energy transfer. We investigate the budget equation for GS Reynolds stress in turbulent channel flows accompanied by the SGS stress decomposition. In addition, we examine the medium and coarse filter length cases; the conventional eddy-viscosity models can fairly predict the mean velocity profile for the medium filter case and fails for the coarse filter case. The budget *

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Section: A Decomposition Of Sgs Stressmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Necessity of anisotropic subgrid-scale stress in coarse large-eddy simulation

Inagaki¹,

Kobayashi²

2023

Preprint

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“…This is likely invalid in 3DTBL, similar to the well-known misalignment of the Reynolds stress tensor and the mean strain-rate tensor in 3DTBLs in the RANS context. Agrawal et al (2022) recently proposed a dynamic tensor-coefficient Smagorinsky model (DTCSM), where the SGS stress tensor is related to the filtered rate-of-strain tensor through a second-order tensor of model coefficients with four independent parameters. This tensor-coefficient-based SGS model is also examined under the same numerical set-up as with the DSM model.…”

Section: Author Orcidsmentioning

confidence: 99%

“…The Vreman model (Vreman 2004) is used to close the SGS stress and heat flux. In Appendix A, the effect of SGS stress models is discussed along with the results obtained with the dynamic Smagorinsky model and dynamic tensor-coefficient Smagorinsky model (Moin et al 1991;Lilly 1992;Agrawal et al 2022).…”

Section: Flow Solver and Subgrid Scale (Sgs) / Near-wall Modellingmentioning

confidence: 99%

Wall-modelled large-eddy simulation of three-dimensional turbulent boundary layer in a bent square duct

Hayat

Park

2023

J. Fluid Mech.

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We conduct wall-modelled large-eddy simulation (WMLES) of a pressure-driven three-dimensional turbulent boundary layer developing on the floor of a bent square duct to investigate the predictive capability of three widely used wall models, namely, a simple equilibrium stress model, an integral non-equilibrium model, and a partial differential equation (PDE) non-equilibrium model. The numerical results are compared with the experiment of Schwarz & Bradshaw (J. Fluid Mech., vol. 272, 1994, pp. 183–210). While the wall-stress magnitudes predicted by the three wall models are comparable, the PDE non-equilibrium wall model produces a substantially more accurate prediction of the wall-stress direction, followed by the integral non-equilibrium wall model. The wall-stress direction from the wall models is shown to have separable contributions from the equilibrium stress part and the integrated non-equilibrium effects, where how the latter is modelled differs among the wall models. The triangular plot of the wall-model solution reveals different capabilities of the wall models in representing variation of flow direction along the wall-normal direction. In contrast, the outer LES solution is unaffected by the type of wall model used, resulting in nearly identical predictions of the mean and turbulent statistics in the outer region for all the wall models. This is explained by the vorticity dynamics and the inviscid skewing mechanism of generating the mean three-dimensionality. Finally, the LES solution in the outer layer is used to study the anisotropy of turbulence. In contrast to the canonical two-dimensional wall turbulence, the Reynolds stress anisotropy exhibits strong non-monotonic behaviour with increasing wall distance.

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