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

Rasam, Amin; Brethouwer, Geert; Johansson, A.

doi:10.1017/jfm.2013.81

Cited by 21 publications

(19 citation statements)

References 60 publications

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“…In this region, no viscous convective subrange occurs, and mixing spectra resemble flow spectra as they appear in turbulent jets of subcritical gases. Such a finding suggests that tensorial heat diffusivity models (e.g., [47][48][49][50]) might be appropriate for supercritical flows, in particular for fluids with strong liquid-like character.…”

Section: Thermal Transportmentioning

confidence: 97%

Thermal Transport and Entropy Production Mechanisms in a Turbulent Round Jet at Supercritical Thermodynamic Conditions

Ries

Janicka

Sadiki

2017

Entropy

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Abstract:In the present paper, thermal transport and entropy production mechanisms in a turbulent round jet of compressed nitrogen at supercritical thermodynamic conditions are investigated using a direct numerical simulation. First, thermal transport and its contribution to the mixture formation along with the anisotropy of heat fluxes and temperature scales are examined. Secondly, the entropy production rates during thermofluid processes evolving in the supercritical flow are investigated in order to identify the causes of irreversibilities and to display advantageous locations of handling along with the process regimes favorable to mixing. Thereby, it turned out that (1) the jet disintegration process consists of four main stages under supercritical conditions (potential core, separation, pseudo-boiling, turbulent mixing), (2) causes of irreversibilities are primarily due to heat transport and thermodynamic effects rather than turbulence dynamics and (3) heat fluxes and temperature scales appear anisotropic even at the smallest scales, which implies that anisotropic thermal diffusivity models might be appropriate in the context of both Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) approaches while numerically modeling supercritical fluid flows.

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Section: Thermal Transportmentioning

confidence: 97%

Thermal Transport and Entropy Production Mechanisms in a Turbulent Round Jet at Supercritical Thermodynamic Conditions

Ries

Janicka

Sadiki

2017

Entropy

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“…Performance of the SGS scalar flux model depends on the SGS stress model 3,6 , since the scalar field depend on the predicted velocity field. This is also true for the EASFM which directly includes the SGS stresses in its formulation, see equation (12).…”

Section: B Mean and Rms Of Scalar And Scalar Fluxesmentioning

confidence: 99%

“…Performance of the EASM, a nonlinear mixed model, has been demonstrated for the case of turbulent channel flow at various Reynolds numbers and grid resolutions, channel flow with system rotation in different directions and channel flow with periodic constrictions [1][2][3][4] . These studies illustrate the importance of the nonlinear SGS stress term in the EASM and showed that the assumption of an isotropic linear relationship between the SGS stress and resolved strain-rate tensor, as in the eddy-viscosity models, is not valid in wall-bounded turbulent flows where the SGS anisotropy is appreciable.…”

Section: Introductionmentioning

confidence: 99%

“…It has been successfully applied to LES of channel flow with passive scalar transport with and without system rotation 3 , where it has been shown that the proper tensor eddydiffusivity formulation of the EASFM improves LES predictions. Since the quality of scalar predictions is closely related to the velocity predictions 3,6 , it is natural to use the EASFM in combination with the EASM. The EASM and EASFM not only improve the predictions of the individual SGS stresses and scalar fluxes over the isotropic eddy-viscosity and eddydiffusivity models, but also improve the characteristics of the SGS dissipation of energy 2,3 at a wide range of resolutions, as demonstrated by a SGS activity parameter analysis 7 .…”

Section: Introductionmentioning

confidence: 99%

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A stochastic extension of the explicit algebraic subgrid-scale models

2014

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PostprintThis is the accepted version of a paper published in Physics of fluids. This paper has been peerreviewed but does not include the final publisher proof-corrections or journal pagination.Citation for the original published paper (version of record):Rasam, A., Brethouwer, G., Johansson, A. (2014) A stochastic extension of the explicit algebraic subgrid-scales models. Moreover, the nonalignment between the SGS stress and resolved strain-rate tensors predicted by the EASM with stochastic extension is in much closer agreement with DNS data. a) Electronic mail: rasam@mech.kth.se.

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“…In the previous work, this model has been thoroughly tested in canonical test cases such as homogeneous shear flow and turbulent channel flow, both with stable stratification. It should be noted that similar approaches have been used in LES in both the atmospheric and engineering communities (Findikakis and Street 1979;Wyngaard 2004;Rasam et al 2013Rasam et al , 2014Enriquez and Street 2014).…”

Section: Introductionmentioning

confidence: 99%

Study of Transitions in the Atmospheric Boundary Layer Using Explicit Algebraic Turbulence Models

Lazeroms

Svensson

Bazile

et al. 2016

Boundary-Layer Meteorol

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We test a recently developed engineering turbulence model, a so-called explicit algebraic Reynolds-stress (EARS) model, in the context of the atmospheric boundary layer. First of all, we consider a stable boundary layer used as the well-known first test case from the Global Energy and Water Cycle Experiment Atmospheric Boundary Layer Study (GABLS1). The model is shown to agree well with data from large-eddy simulations (LES), and this agreement is significantly better than for a standard operational scheme with a prognostic equation for turbulent kinetic energy. Furthermore, we apply the model to a case with a (idealized) diurnal cycle and make a qualitative comparison with a simpler first-order model. Some interesting features of the model are highlighted, pertaining to its stronger foundation on physical principles. In particular, the use of more prognostic equations in the model is shown to give a more realistic dynamical behaviour. This qualitative study is the first step towards a more detailed comparison, for which additional LES data are needed.

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

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

Cited by 21 publications

References 60 publications

Thermal Transport and Entropy Production Mechanisms in a Turbulent Round Jet at Supercritical Thermodynamic Conditions

Thermal Transport and Entropy Production Mechanisms in a Turbulent Round Jet at Supercritical Thermodynamic Conditions

A stochastic extension of the explicit algebraic subgrid-scale models

Study of Transitions in the Atmospheric Boundary Layer Using Explicit Algebraic Turbulence Models

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