Effect of subgrid models on the computed interscale energy transfer in isotropic turbulence
TL;DR: In this paper, a priori analysis showed that the subgrid stress and the sub-grid energy flux predicted by the scale similarity model, and subgrid kinetic energy model (with fixed coefficients) correlate reasonably well with exact data, while the Smagorinsky's eddy viscosity model showed relatively poor agreement.
About: This article is published in Computers & Fluids.The article was published on 1996-02-01. It has received 263 citations till now. The article focuses on the topics: Turbulence modeling & Turbulence.
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TL;DR: In this article, a review of scale-invariance properties of high-Reynolds-number turbulence in the inertial range is presented, focusing on dynamic and similarity subgrid models and evaluating how well these models reproduce the true impact of the small scales on large scale physics and how they perform in numerical simulations.
Abstract: ▪ Abstract Relationships between small and large scales of motion in turbulent flows are of much interest in large-eddy simulation of turbulence, in which small scales are not explicitly resolved and must be modeled. This paper reviews models that are based on scale-invariance properties of high-Reynolds-number turbulence in the inertial range. The review starts with the Smagorinsky model, but the focus is on dynamic and similarity subgrid models and on evaluating how well these models reproduce the true impact of the small scales on large-scale physics and how they perform in numerical simulations. Various criteria to evaluate the model performance are discussed, including the so-called a posteriori and a priori studies based on direct numerical simulation and experimental data. Issues are addressed mainly in the context of canonical, incompressible flows, but extensions to scalar-transport, compressible, and reacting flows are also mentioned. Other recent modeling approaches are briefly introduced.
1,395 citations
TL;DR: In this paper, a monotonically integrated large eddy simulation (MILES) approach is proposed, which involves solving the unfiltered Navier-Stokes equations (NSEs) using high-resolution monotone algorithms.
Abstract: With a view to ensure that proper interaction between resolvable or grid scale and subgrid scale (SGS) motions are mimicked, it is vital to determine the necessary physics that must be built into the SGS models. In ordinary large eddy simulation (LES) approaches, models are introduced for closure in the low-pass filtered Navier-Stokes equations (NSEs), which are the ones solved numerically. A promising LES approach is monotonically integrated LES (MILES), which involves solving the unfiltered NSE using high-resolution monotone algorithms; in this approach, implicit SGS models, provided by intrinsic nonlinear high-frequency filters built into the convection discretization, are coupled naturally to the resolvable scales of the flow. Formal properties of the effectual SGS modeling using MILES are documented using databases of simulated homogeneous turbulence and transitional freejets; mathematical and physical aspects of (implicit) SGS modeling through the use of nonlinear flux limiters are addressed in this context
391 citations
TL;DR: In this paper, a large-eddy simulation of turbulent premixed reacting flows in a gas turbine combustor (General Electric's lean premixed dry low-NOx LM6000) has been carried out to evaluate the potential of LES for design studies of realistic hardware.
Abstract: Large-eddy simulation (LES) of turbulent premixed reacting flows in a gas turbine combustor (General Electric's lean premixed dry low-NOx LM6000) has been carried out to evaluate the potential of LES for design studies of realistic hardware. A flamelet model for the premixed flame is combined with a dynamic model for the subgrid kinetic energy to simulate the propagation of the turbulent flame in this high swirl and high Reynolds number flow. Comparison of the computed results with experimental data indicate good agreement in spite of relatively coarse grid resolution employed in the LES. These results provide significant confidence that LES capability for design studies of practical interest is feasible in the near future.
357 citations
TL;DR: In this article, a large eddy simulation (LES) model is compared with the Subgrid Scale (SGS) model for Taylor Re numbers between 35 and 248 using various SGS models, representative of the contemporary state of the art.
Abstract: Recently, a number of studies have indicated that Large Eddy Simulation (LES) models are fairly insensitive to the adopted Subgrid Scale (SGS) models. In order to study this and to gain further insight into LES, simulations of forced and decaying homogeneous isotropic turbulence have been performed for Taylor Re numbers between 35 and 248 using various SGS models, representative of the contemporary state of the art. The predictive capability of the LES concept is analyzed by comparison with DNS data and with results obtained from a theoretical model of the energy spectrum. The resolved flow is examined by visualizing the morphology and by analyzing the distribution of resolved enstrophy, rate of strain, stretching, SGS kinetic energy, and viscosity. Furthermore, the correlation between eigenvalues of the resolved rate of strain tensor and the vorticity is investigated. Although the gross features of the flow appear independent of the SGS model, pronounced differences between the models become apparent whe...
283 citations
TL;DR: In this paper, a review of the physical models and advanced methods used in computational studies of gas-liquid two-phase jet flows encountered in atomization and spray processes is presented.
255 citations
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TL;DR: In this article, a new eddy viscosity model is presented which alleviates many of the drawbacks of the existing subgrid-scale stress models, such as the inability to represent correctly with a single universal constant different turbulent fields in rotating or sheared flows, near solid walls, or in transitional regimes.
Abstract: One major drawback of the eddy viscosity subgrid‐scale stress models used in large‐eddy simulations is their inability to represent correctly with a single universal constant different turbulent fields in rotating or sheared flows, near solid walls, or in transitional regimes. In the present work a new eddy viscosity model is presented which alleviates many of these drawbacks. The model coefficient is computed dynamically as the calculation progresses rather than input a priori. The model is based on an algebraic identity between the subgrid‐scale stresses at two different filtered levels and the resolved turbulent stresses. The subgrid‐scale stresses obtained using the proposed model vanish in laminar flow and at a solid boundary, and have the correct asymptotic behavior in the near‐wall region of a turbulent boundary layer. The results of large‐eddy simulations of transitional and turbulent channel flow that use the proposed model are in good agreement with the direct simulation data.
6,747 citations
TL;DR: In this paper, the subgrid-scale closure method developed by Germano et al. is modified by use of a least squares technique to minimize the difference between the closure assumption and the resolved stresses.
Abstract: The subgrid‐scale closure method developed by Germano et al. is modified by use of a least squares technique to minimize the difference between the closure assumption and the resolved stresses. This modification removes a source of singularity and is believed to improve the method’s applicability.
3,730 citations
01 Sep 1981
TL;DR: In this article, the results of simulations for irrotational strain (plane and axisymmetric), shear, rotation, and relaxation toward isotropy in an incompressible fluid subjected to uniform deformation or rotation are compared with linear theory and experimental data.
Abstract: The direct simulation methods developed by Orszag and Patternson (1972) for isotropic turbulence were extended to homogeneous turbulence in an incompressible fluid subjected to uniform deformation or rotation. The results of simulations for irrotational strain (plane and axisymmetric), shear, rotation, and relaxation toward isotropy following axisymmetric strain are compared with linear theory and experimental data. Emphasis is placed on the shear flow because of its importance and because of the availability of accurate and detailed experimental data. The computed results are used to assess the accuracy of two popular models used in the closure of the Reynolds-stress equations. Data from a variety of the computed fields and the details of the numerical methods used in the simulation are also presented.
993 citations
01 Jul 1980
TL;DR: In this article, the authors analyzed models for subgrid-scale turbulence and showed that the kinetic energy of small-scale motions can be decomposed into two parts: one results from the large scales and is correlated with them, and the other part is uncorrelated which leads to a two-component eddy-viscosity model.
Abstract: The paper analyzes models for subgrid-scale turbulence. The analysis indicates that there is sufficient information in the resolved scales to determine some characteristics of the complete flow field. The kinetic energy of the small-scale motions can be decomposed into two parts: one results from the large scales and is correlated with them, and the other part is uncorrelated which leads to a two-component eddy-viscosity model. The 'production equals dissipation' argument does not apply to the small scales in the decay of turbulence because it does not account for the uncorrelated component. The exchange between the large and small scales takes place mainly between the smallest scales of the former and the largest scales of the latter; this argument is the basis of a new model shown to be superior to the Smagorinsky model (1963).
891 citations
TL;DR: Germano et al. as mentioned in this paper proposed a method for computing coefficients of subgrid-scale eddy viscosity models as a function of space and time, which can be applied to general inhomogeneous flows and does not suffer from the mathematical inconsistencies inherent in the previous formulation.
Abstract: In a previous paper, Germano, et al. (1991) proposed a method for computing coefficients of subgrid-scale eddy viscosity models as a function of space and time. This procedure has the distinct advantage of being self-calibrating and requires no a priori specification of model coefficients or the use of wall damping functions. However, the original formulation contained some mathematical inconsistencies that limited the utility of the model. In particular, the applicability of the model was restricted to flows that are statistically homogeneous in at least one direction. These inconsistencies and limitations are discussed and a new formulation that rectifies them is proposed. The new formulation leads to an integral equation whose solution yields the model coefficient as a function of position and time. The method can be applied to general inhomogeneous flows and does not suffer from the mathematical inconsistencies inherent in the previous formulation. The model has been tested in isotropic turbulence and in the flow over a backward-facing step.
835 citations