A subgrid model for equilibrium chemistry in turbulent flows

Cook, Andrew W.; Riley, James J.

doi:10.1063/1.868111

Cited by 304 publications

(214 citation statements)

References 4 publications

Supporting

Mentioning

207

Contrasting

Unclassified

Order By: Relevance

“…Its use for LES has been proposed by Cook and Riley [39] and since then it has become a standard closure technique in LES, like in RANS. That the beta-pdf probably provides a suitable (although non-exact) description of chemistry subgrid terms, can be seen from the following transformation of the filter integral in one-dimension:…”

Section: Four Sgs Modeling Approaches For Chemical Variables When Permentioning

confidence: 99%

Subgrid Scale Modeling in Large-Eddy Simulation of Turbulent Combustion Using Premixed Flamelet Chemistry

Vreman

Oijen

Goey

et al. 2008

Flow Turbulence Combust

View full text Add to dashboard Cite

Large-eddy simulation (LES) of turbulent combustion with premixed flamelets is investigated in this paper. The approach solves the filtered NavierStokes equations supplemented with two transport equations, one for the mixture fraction and another for a progress variable. The LES premixed flamelet approach is tested for two flows: a premixed preheated Bunsen flame and a partially premixed diffusion flame (Sandia Flame D). In the first case, we compare the LES with a direct numerical simulation (DNS). Four non-trivial models for the chemical source term are considered for the Bunsen flame: the standard presumed beta-pdf model, and three new propositions (simpler than the beta-pdf model): the filtered flamelet model, the shift-filter model and the shift-inversion model. A priori and a posteriori tests are performed for these subgrid reaction models. In the present preheated Bunsen flame, the filtered flamelet model gives the best results in a priori tests. The LES tests for the Bunsen flame are limited to a case in which the filter width is only slightly larger than the flame thickness. According to the a posteriori tests the three models (beta-pdf, filtered flamelet and shift-inversion) show more or less the same results as the trivial model, in which subgrid reaction effects are ignored, while the shift-filter model leads to worse results. Since LES needs to resolve the large turbulent eddies, the LES filter width is bounded by a maximum. For the present Bunsen flame this means that the filter width should be of the order of the flame thickness or smaller. In this regime, the effects of subgrid reaction and subgrid flame wrinkling turn out to be quite modest. The LES-results of the second case (Sandia Flame D) are compared to experimental data. Satisfactory agreement is obtained for the main species. Comparison is made between different eddy-viscosity models for the subgrid turbulence, and the Smagorinsky eddy-viscosity is found to give worse results than eddy-viscosities that are not dominated by the mean shear.

show abstract

Section: Four Sgs Modeling Approaches For Chemical Variables When Permentioning

confidence: 99%

Subgrid Scale Modeling in Large-Eddy Simulation of Turbulent Combustion Using Premixed Flamelet Chemistry

Vreman

Oijen

Goey

et al. 2008

Flow Turbulence Combust

View full text Add to dashboard Cite

show abstract

“…͑17͒. Despite the availability of other algebraic variance models, 7 dynamic models are preferred in combustion modeling because they eliminate the need to predetermine a model coefficient and perform well in a priori tests. 8,14 However, a weakness of the coefficient estimation procedure is its reliance, through test filtering, on the high wavenumber components of the filtered scalar field that are most affected by numerical error.…”

Section: ͑12͒mentioning

confidence: 99%

“…The first approach relies on scaling or equilibrium assumptions to obtain algebraic expressions for the variance. 7,8 This category includes the widely used dynamic model, 8 which relates the variance to the magnitude of filtered scalar gradients. The dynamic procedure eliminates the need to specify model coefficients a priori.…”

Section: Background and Motivationmentioning

confidence: 99%

A posteriori analysis of numerical errors in subfilter scalar variance modeling for large eddy simulation

Kaul

Raman

2011

Physics of Fluids

View full text Add to dashboard Cite

“…The ␤ PDF is then specified based on the subgrid mean and variance that determine the two parameters of the model. Cook and Riley 44 proposed calculating the subgrid variance directly from the resolved scalar field using a scale similarity model. Comparisons with DNS generated scalar fields showed that integrated mean product concentrations are reasonably well predicted using this approach, despite finding that the actual subgrid PDFs are not well predicted by the ␤ form ͑see also Refs.…”

Section: Subgrid Probability Density Functionsmentioning

confidence: 99%

Direct numerical simulation and subgrid analysis of a transitional droplet laden mixing layer

Miller

Bellan

2000

Physics of Fluids

View full text Add to dashboard Cite

A priori subgrid analysis of temporal mixing layers with evaporating droplets Physics of Fluids 12, 1573 (2000); 10.1063/1.870405Direct numerical simulation and subgrid analysis of a transitional droplet laden mixing layer Richard S. Miller a) and Josette Bellan Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109-8099 ͑Received 13 February 1999; accepted 1 December 1999͒ Direct numerical simulations of a temporally developing, droplet laden mixing layer undergoing transition to mixing turbulence are conducted. The formulation includes complete two-way couplings of mass, momentum, and energy. As many as 18ϫ10 6 grid points are used to discretize the Eulerian gas phase equations and up to 5.7ϫ10 6 initially polydisperse evaporating droplets are tracked in the Lagrangian reference frame. The complete transition to mixing turbulence is captured for several of the higher Reynolds number simulations and it is observed that increasing the droplet mass loading ratio results in a more ''natural'' turbulence characterized by increased rotational energy and less influence of the initial forcing perturbations. An increased mass loading also results in increased droplet organization within the layer. An a priori subgrid analysis is then conducted which shows that neglecting subgrid velocity fluctuations in the context of large eddy simulations may result in significant errors in predicting the droplet drag force for Stokes numbers Stϳ1 ͑with the flow time scale based on the mean velocity difference and initial vorticity thickness͒. Similar possible errors of lesser magnitude are also observed for the droplet heat flux and evaporation rate when thermodynamic subgrid fluctuations are neglected. An extension of the eddy interaction model commonly used in Reynolds-averaged simulations is then proposed in order to account for the missing subgrid information. Probability density functions ͑PDFs͒ of the subgrid fluctuations calculated across homogeneous planes are shown to be highly intermittent, particularly near the laminar-turbulent boundaries of the mixing layer. However, the actual subgrid PDFs calculated locally are much less intermittent and may be adequately modeled by the Gaussian distribution throughout the majority of the mixing layer. A scale similarity model is then employed to predict both the velocity and thermodynamic subgrid variances. The similarity model is well correlated with the actual subgrid variances and shows good agreement in predicting the local fluctuation intensities when a filter width-dependent model constant is used. The subgrid fluctuation variances acting on the droplets are then shown to be well modeled if the Eulerian subgrid variance model is interpolated to the droplet locations.

show abstract

A subgrid model for equilibrium chemistry in turbulent flows

Cited by 304 publications

References 4 publications

Subgrid Scale Modeling in Large-Eddy Simulation of Turbulent Combustion Using Premixed Flamelet Chemistry

Subgrid Scale Modeling in Large-Eddy Simulation of Turbulent Combustion Using Premixed Flamelet Chemistry

A posteriori analysis of numerical errors in subfilter scalar variance modeling for large eddy simulation

Direct numerical simulation and subgrid analysis of a transitional droplet laden mixing layer

Contact Info

Product

Resources

About