A dynamic localization model for large-eddy simulation of turbulent flows

Ghosal, Sandip; Lund, Thomas S.; Moin, Parviz; Akselvoll, K.

doi:10.1017/s0022112095000711

Cited by 663 publications

(363 citation statements)

References 14 publications

(24 reference statements)

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“…If in a particular application one aims at the prediction of a time-reversed flow without risking an unlimited amount of backscatter, one can use one of the models given by (10) and (11). A more sophisticated, but also more physical, procedure was proposed by Ghosal et al 26 by basing the flux of energy to the small scales on the subgrid scale energy, which was computed using a transport equation for the Reynolds averaged subgrid scales. This procedure implicitly assumes that the net energy flux from the resolved scales to the subgrid scales is determined by the subgrid energy.…”

Section: Results For Reversed Turbulence From Large Eddy Simulationsmentioning

confidence: 99%

Time-reversibility of Navier-Stokes turbulence and its implication for subgrid-scale models

Fang¹,

Bos²,

Shao³

et al. 2011

ERCOFTAC Series

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Among existing subgrid scale models for large-eddy simulation (LES) some are time-reversible in the sense that the dynamics evolve backwards in time after a transformation u → −u at every point in space. In practice, reversible subgrid models reduce the numerical stability of the simulations since the effect of the subgrid scales is no longer strictly dissipative. This lack of stability constitutes often a criterion to reject this kind of models. The aim of this paper is to examine whether timereversibility can constitute a criterion that a subgrid model has to fulfill, or has not to. Thereto we investigate by direct numerical simulation the time-dependence of the kinetic energy of the resolved scales when the velocity is reversed in all or part of the lengthscales of the turbulent flow. These results are compared with results from existing LES subgrid models. It is argued that the criterion of time-reversibility to assess subgrid models is incompatible with the main underlying assumption of LES.

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Section: Results For Reversed Turbulence From Large Eddy Simulationsmentioning

confidence: 99%

Time-reversibility of Navier-Stokes turbulence and its implication for subgrid-scale models

Fang¹,

Bos²,

Shao³

et al. 2011

ERCOFTAC Series

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“…where P = p−1/3τ kk denotes the modified pressure, b i the kinematic body force per unit volume, S ij the symmetric part of the deformation rate tensor, t the time, τ ij the SGS stress tensor, and E SG the SGS kinetic energy; the negative trace of τ kk follows from the positive filter kernel (see, Ghosal et al , 1995). In the following we drop use of the hat for convenience unless explicitly required.…”

Section: Governing Equationsmentioning

confidence: 99%

Flow around a cube in a turbulent boundary layer: LES and experiment

Lim

Thomas

Castro

2009

Journal of Wind Engineering and Industrial Aerodynamics

136

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We present a numerical simulation of flow around a surface mounted cube placed in a turbulent boundary layer which, although representing a typical wind environment, has been specifically tailored to match a series of wind tunnel observations. The simulations were carried out at a Reynolds number, based on the velocity U at the cube height h, of 20, 000 -large enough that many aspects of the flow are effectively Reynolds number independent. The turbulence intensity was about 18% at the cube height, and the integral length scale L u x was about 0.8 times the cube height h. The Jenson number Je = h/z0, based on the approach flow roughness length z0, was 600, to match the wind tunnel situation. The computational mesh was uniform with a spacing of h/32, aiding rapid convergence of the multigrid solver, and the governing equations were discretised using second order finite differences within a parallel multiblock environment. The results presented include detailed comparison between measurements and LES computations of both the inflow boundary layer and the flow field around the cube including mean and fluctuating surface pressures. It is concluded that provided properly formulated inflow and surface boundary conditions are used, LES is now a viable tool for use in wind engineering problems concerning flow over isolated bodies. In particular, both mean and fluctuating surface pressures can be obtained with a similar degree of uncertainty as usually associated with wind tunnel modelling.

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“…3,4 Some mathematical inconsistencies which arise in the dynamical formulation can be resolved by casting the problem in variational form, resulting in the dynamic localization model. 5 In applications, simplified solutions to the difficulties arising in the dynamic procedure are widely used, for example plane averaging in homogeneous directions 3 or approximate localization. 6 A related class of SGS models are the spectral eddyviscosity models.…”

Section: Introductionmentioning

confidence: 99%

A physical-space version of the stretched-vortex subgrid-stress model for large-eddy simulation

2000

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A physical-space version of the stretched-vortex subgrid-stress model is presented and applied to large-eddy simulations of incompressible flows. This version estimates the subgrid-kinetic energy required for evaluation of the subgrid-stress tensor using local second-order structure-function information of the resolved velocity field at separations of order the local cell size. A relation between the structure function and the energy spectrum is derived using the kinematic assumptions of the stretched-vortex model for locally homogeneous anisotropic turbulence. Results of large-eddy simulations using this model are compared to experimental and direct numerical simulation data. Comparisons are shown for the decay of kinetic energy and energy spectra of decaying isotropic turbulence and for mean velocities, root-mean-square velocity fluctuations and turbulence-kinetic energy balances of channel flow at three different Reynolds numbers.

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A dynamic localization model for large-eddy simulation of turbulent flows

Cited by 663 publications

References 14 publications

Time-reversibility of Navier-Stokes turbulence and its implication for subgrid-scale models

Time-reversibility of Navier-Stokes turbulence and its implication for subgrid-scale models

Flow around a cube in a turbulent boundary layer: LES and experiment

A physical-space version of the stretched-vortex subgrid-stress model for large-eddy simulation

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