<i>A priori</i>study of subgrid-scale flux of a passive scalar in isotropic homogeneous turbulence

Chumakov, Sergei

doi:10.1103/physreve.78.036313

Cited by 39 publications

(42 citation statements)

References 41 publications

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“…The formulation of the new model is such that its prediction of the subgrid-scale (SGS) scalar flux vector is not necessarily aligned with the resolved scalar gradient vector. It uses the SGS stress tensor in its formulation which is in agreement with the recent findings of Chumakov (2008) where it has been pointed out that the direction of the SGS scalar flux vector is connected to the eigenvalues and eigenvectors of the SGS stress tensor. Since the new model includes the rotation-rate tensor in its formulation, it accounts for rotational effects at the SGS level in a natural way.…”

Section: Discussionsupporting

confidence: 71%

An explicit algebraic model for the subgrid-scale passive scalar flux

2013

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Section: Discussionsupporting

confidence: 71%

An explicit algebraic model for the subgrid-scale passive scalar flux

2013

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“…Equation (19) also explains the enstrophy dependence of τ φ orientation observed in Ref. [30]. In regions of low enstrophy (|ω| 2 /2), the e 3 component of Eq.…”

Section: A Explanation For Orientationsupporting

confidence: 59%

Subfilter scalar-flux vector orientation in homogeneous isotropic turbulence

Verma

Blanquart

2014

Phys. Rev. E

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The geometric orientation of the subfilter-scale scalar-flux vector is examined in homogeneous isotropic turbulence. Vector orientation is determined using the eigenframe of the resolved strain-rate tensor. The Schmidt number is kept sufficiently large so as to leave the velocity field, and hence the strain-rate tensor, unaltered by filtering in the viscous-convective subrange. Strong preferential alignment is observed for the case of Gaussian and box filters, whereas the sharp-spectral filter leads to close to a random orientation. The orientation angle obtained with the Gaussian and box filters is largely independent of the filter width and the Schmidt number. It is shown that the alignment direction observed numerically using these two filters is predicted very well by the tensor-diffusivity model. Moreover, preferred alignment of the scalar gradient vector in the eigenframe is shown to mitigate any probable issues of negative diffusivity in the tensor-diffusivity model. Consequentially, the model might not suffer from solution instability when used for large eddy simulations of scalar transport in homogeneous isotropic turbulence. Further a priori tests indicate poor alignment of the Smagorinsky and stretched vortex model predictions with the exact subfilter flux. Finally, strong filter dependence of subfilter scalar-flux orientation suggests that explicit filtering may be preferable to implicit filtering in large eddy simulations.

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“…Details of the individual runs are summarized in Table I. 053010-3 Our simulations have been well validated by means of extensive and detailed comparison with the results of other investigations. Further details of the performance of our code including verification of isotropy may be found in the thesis by Yoffe [37], along with values for the Kolmogorov constant and velocity-derivative skewness; and a direct comparison with the freely available pseudospectral code hit3d [38,39]. Furthermore, our data reproduce the characteristic behavior for the plot of the dimensionless dissipation rate C ε against R λ [40], and agree closely with other representative results in the literature, such as the work by Wang, Chen, Brasseur, and Wyngaard [41], Cao, Chen, and Doolen [42], Gotoh, Fukayama, and Nakano [43], Kaneda, Ishihara, Yokokawa, Itakura, and Uno [33], Donzis, Sreenivasan, and Yeung [44], and Yeung, Donzis, and Sreenivasan [45], although there are some differences in forcing methods.…”

Section: Methodsmentioning

confidence: 99%

Spectral analysis of structure functions and their scaling exponents in forced isotropic turbulence

et al. 2014

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This version is available at https://strathprints.strath.ac.uk/50699/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. The pseudospectral method, in conjunction with a technique for obtaining scaling exponents ζ n from the structure functions S n (r), is presented as an alternative to the extended self-similarity (ESS) method and the use of generalized structure functions. We propose plotting the ratio |S n (r)/S 3 (r)| against the separation r in accordance with a standard technique for analyzing experimental data. This method differs from the ESS technique, which plots S n (r)againstS 3 (r), with the assumption S 3 (r) ∼ r. Using our method for the particular case of S 2 (r) we obtain the result that the exponent ζ 2 decreases as the Taylor-Reynolds number increases, with ζ 2 → 0.679 ± 0.013 as R λ →∞. This supports the idea of finite-viscosity corrections to the K41 prediction for S 2 , and is the opposite of the result obtained by ESS. The pseudospectral method also permits the forcing to be taken into account exactly through the calculation of the energy input in real space from the work spectrum of the stirring forces.

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A prioristudy of subgrid-scale flux of a passive scalar in isotropic homogeneous turbulence

Cited by 39 publications

References 41 publications

An explicit algebraic model for the subgrid-scale passive scalar flux

An explicit algebraic model for the subgrid-scale passive scalar flux

Subfilter scalar-flux vector orientation in homogeneous isotropic turbulence

Spectral analysis of structure functions and their scaling exponents in forced isotropic turbulence

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