Dynamic subfilter-scale stress model for large-eddy simulations

Rouhi, Amirreza; Piomelli, Ugo; Geurts, Bernardus J.

doi:10.1103/physrevfluids.1.044401

Cited by 35 publications

(23 citation statements)

References 39 publications

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“…The behavior of SGS models close to the wall has been improved in recent works such as the constrained LES by Chen et al [48], the integral length-scale approximation model by Rouhi et al [49], and the explicit algebraic Table 1. model by Rasam et al [50], among others. These approaches reduce substantially the grid requirements by modifying the SGS model near the wall while maintaining the no-slip boundary condition.…”

Section: The Challenge Of Quantifying the Performance Of Sgs Models Imentioning

confidence: 99%

Error scaling of large-eddy simulation in the outer region of wall-bounded turbulence

Lozano-Durán

Bae

2019

Journal of Computational Physics

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A B S T R A C TWe study the error scaling properties of large-eddy simulation (LES) in the outer region of wall-bounded turbulence at moderately high Reynolds numbers. In order to avoid the additional complexity of wall-modeling, we perform LES of turbulent channel flows in which the no-slip condition at the wall is replaced by a Neumann condition supplying the exact mean wall-stress. The statistics investigated are the mean velocity profile, turbulence intensities, and kinetic energy spectra. The errors follow (∆/L) α Re γ τ , where ∆ is the characteristic grid resolution, Re τ is the friction Reynolds number, and L is the meaningful length-scale to normalize ∆ in order to collapse the errors across the wall-normal distance. We show that ∆ can be expressed as the L 2 -norm of the grid vector and that L is well represented by the ratio of the friction velocity and mean shear. The exponent α is estimated from theoretical arguments for each statistical quantity of interest and shown to roughly match the values computed by numerical simulations. For the mean profile and kinetic energy spectra, α ≈ 1, whereas the turbulence intensities converge at a slower rate α < 1. The exponent γ is approximately 0, i.e. the LES solution is independent of the Reynolds number. The expected behavior of the turbulence intensities at high Reynolds numbers is also derived and shown to agree with the classic log-layer profiles for grid resolutions lying within the inertial range. Further examination of the LES turbulence intensities and spectra reveals that both quantities resemble their filtered counterparts from direct numerical simulation (DNS) data, but that the mechanism responsible for this similarity is related to the balance between the input power and dissipation rather than to filtering.

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Section: The Challenge Of Quantifying the Performance Of Sgs Models Imentioning

confidence: 99%

Error scaling of large-eddy simulation in the outer region of wall-bounded turbulence

Lozano-Durán

Bae

2019

Journal of Computational Physics

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“…For example, incompatibilities between model requirements and the observation that even some very successful subgrid-scale models do not satisfy all the discussed requirements, warrant an assessment of the practical importance and significance of each of the model requirements. Furthermore, the fact that the velocity-gradient-based subgrid-scale models we considered here do not comply with scale invariance, calls for a detailed analysis of the symmetry preservation properties of the dynamic procedure [13], of other techniques that provide estimates of the turbulent kinetic energy and energy dissipation rate like the integral-length scale approximation [30,34], and of flow-dependent definitions of the subgrid characteristic length scale in general. We would also like to investigate the behavior of subgrid-scale models that contain terms that are nonlinear in the rate-of-strain and rate-of-rotation tensors, particularly to study their ability to describe transport processes in flows.…”

Section: Discussionmentioning

confidence: 99%

Physical consistency of subgrid-scale models for large-eddy simulation of incompressible turbulent flows

2017

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We study the construction of subgrid-scale models for large-eddy simulation of incompressible turbulent flows. In particular, we aim to consolidate a systematic approach of constructing subgrid-scale models, based on the idea that it is desirable that subgrid-scale models are consistent with the mathematical and physical properties of the Navier-Stokes equations and the turbulent stresses.To that end, we first discuss in detail the symmetries of the Navier-Stokes equations, and the near-wall scaling behavior, realizability and dissipation properties of the turbulent stresses. We furthermore summarize the requirements that subgrid-scale models have to satisfy in order to preserve these important mathematical and physical properties. In this fashion, a framework of model constraints arises that we apply to analyze the behavior of a number of existing subgrid-scale models that are based on the local velocity gradient. We show that these subgrid-scale models do not satisfy all the desired properties, after which we explain that this is partly due to incompatibilities between model constraints and limitations of velocity-gradient-based subgrid-scale models. However, we also reason that the current framework shows that there is room for improvement in the properties and, hence, the behavior of existing subgrid-scale models. We furthermore show how compatible model constraints can be combined to construct new subgrid-scale models that have desirable properties built into them. We provide a few examples of such new models, of which a new model of eddy viscosity type, that is based on the vortex stretching magnitude, is successfully tested in large-eddy simulations of decaying homogeneous isotropic turbulence and turbulent plane-channel flow.

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“…In a different approach Colosqui & Oberai (2008) derived an expression for the Smagorinsky length scale by an energetic balance and applying the Kolmogorov hypothesis of isotropy of the small turbulent scales. Differently, Piomelli et al (2015) and Rouhi et al (2016), determine the effective filter size in function of a properly defined integral length scale. On the other hand, anisotropic filter lengths have been used in conjunction with anisotropic subgrid scale models (Bardina et al 1980(Bardina et al , 1983aAbbà et al 2017).…”

Section: First-order Modellingmentioning

confidence: 99%

General formalism for a reduced description and modelling of momentum and energy transfer in turbulence

2019

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Based on hierarchies of filter lengths, the large eddy decomposition and the related subgrid stresses are recognized to represent generalized central moments for the study and modelling of the different modes composing turbulence. In particular, the subgrid stresses and the subgrid dissipation are shown to be alternative observables for quantitatively assessing the scale-dependent properties of momentum flux (subgrid stresses) and the energy exchange between the large and small scales (subgrid dissipation). In this work we present a theoretical framework for the study of the subgrid stress and dissipation. Starting from an alternative decomposition of the turbulent stresses, a new formalism for their approximation and understanding is proposed which is based on a tensorial turbulent viscosity. The derived formalism highlights that every decomposition of the turbulent stresses is naturally approximated by a general form of turbulent viscosity tensor based on velocity increments which is then recognized to be a peculiar property of small-scale stresses in turbulence. The analysis in a turbulent channel shows the rich physics of the small-scale stresses which is unveiled by the tensorial formalism and usually missed in scalar approaches. To further exploit the formalism, we also show how it can be used to derive new modelling approaches. The proposed models are based on the second- and third-order inertial properties of the grid element. The basic idea is that the structure of the integration volume for filtering (either implicit or explicit) impacts the anisotropy and inhomogeneity of the filtered-out motions and, hence, this information could be leveraged to improve the prediction of the main unknown features of small-scale turbulence. The formalism provides also a rigorous definition of characteristic lengths for the turbulent stresses, which can be computed in every type of computational elements, thus overcoming the rather elusive definition of filter length commonly employed in more classical models. A preliminary analysis in a turbulent channel shows reasonable results. In order to solve numerical stability issues, a tensorial dynamic procedure for the evolution of the model constants is also developed. The generality of the procedure is such that it can be employed also in more conventional closures.

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Dynamic subfilter-scale stress model for large-eddy simulations

Cited by 35 publications

References 39 publications

Error scaling of large-eddy simulation in the outer region of wall-bounded turbulence

Error scaling of large-eddy simulation in the outer region of wall-bounded turbulence

Physical consistency of subgrid-scale models for large-eddy simulation of incompressible turbulent flows

General formalism for a reduced description and modelling of momentum and energy transfer in turbulence

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