Study of scalar macro- and microstructures in a confined jet

Kornev, Nikolaĭ; Zhdanov, V. L.; Hassel, Egon

doi:10.1016/j.ijheatfluidflow.2008.03.011

Cited by 13 publications

(7 citation statements)

References 20 publications

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“…Owing to the higher signal enhancement, the mixture fraction fluctuations as presented here were lower (about 40%) at x/D = 9.0 than those measured in [12], but they correlated with the ones presented in [25] (here the signal enhancement was also intense). Two-maximum profiles of the reaction product fluctuations almost degraded at a distance of x/D = 7 (x/d = 35), whereas they were still observed at x/d = 40 in the planar reacting jet [6].…”

Section: Mean and Fluctuation Mixing Parameterssupporting

confidence: 75%

“…It is clearly seen that there also exists the stratified flow structure created in the vortex after it has been destructed: there are a lot of different-concentration thin lamellae. The investigations of the fine-grained structure of the scalar field in the turbulent flows revealed that the dissipation rate was concentrated just in the thin sheet-like strained laminar diffusion layers between adjacent different-concentration scalar layers [14,25]. So, molecular mixing took place, obviously, at the boundaries of the lamella.…”

Section: Mean and Fluctuation Mixing Parametersmentioning

confidence: 99%

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Development of macro- and micromixing in confined flows of reactive fluids

Zhdanov

Chorny

2011

International Journal of Heat and Mass Transfer

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Section: Mean and Fluctuation Mixing Parameterssupporting

confidence: 75%

Section: Mean and Fluctuation Mixing Parametersmentioning

confidence: 99%

Development of macro- and micromixing in confined flows of reactive fluids

Zhdanov

Chorny

2011

International Journal of Heat and Mass Transfer

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“…Comparisons between experimental data and RANS simulations of other reacting flows in a confined coaxial jet have also been studied (Chorny and Zhdanov, 2012). Kornev et al (2008) has studied the development of scalar fields in experiments with weakly confined coaxial jets.…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of a coaxial jet with a synthetic turbulent inlet

Abboud

Smith

2014

International Journal of Heat and Fluid Flow

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This study analyzed the effects of two methods of synthetic inlet turbulence on the accuracy of coaxial, circular jet simulations with regards to experimental data. The two methods that were utilized in the study were a digital filter method and a synthetic eddy method. This study examines the implementation of these methods into an academic LES code, with extensive evaluation of the simulation data compared to experimental results. The results in the paper are presented for two different mesh resolutions, 22 and 8 million cells. The simulations were performed for three different velocity ratios of the annular to the inner jet: 0.0, 1.0 and 1.5. The inlet methods were utilized in two ways, one by setting the velocity fluctuation profile based on experimental data of the inlet flow, the second by setting an estimated isotropic-fluctuation profile. In this way, using the estimated method can be compared to using the prescribed fluctuations, which may not be usable if experimental data of the inlet is not available. When comparing the centerline profiles to the velocity data for the turbulent inlet, the data for velocity ratios 1.0 and 1.5 were improved compared to the experimental profiles. However, for the velocity ratio 0.0 case velocity data when using the turbulent inlet the data showed significant decay and did not match experimental profiles in the far field of the jet. The radial data for a velocity ratio of 0.0 showed better agreement with the experimental data in the jet spreading to develop the proper velocity profile. The velocity fluctuation data was the most accurate in the near field region when the turbulent inlet was used. A comparison can also be made between using a prescribed fluctuation inlet and just using the approximated

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“…Both experiments, [13,15] and DNS, e.g. [16], indicate that the m.e. thickness ζ(t) scales with but (much) larger than the Kolmogorov scale, while its length ξ(t) is much larger than the thickness, going up to sizes comparable with the integral length scale; this explains the particular choice of m.e.…”

Section: Eulerian Balance Equations Corresponding To Me Methodsmentioning

confidence: 90%

Mesoscale elements description of turbulent flow

Burluka

2020

Applied Mathematical Modelling

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This work proposes to describe a turbulent flow using a set of mesoscale elements, that is fluid elements of small, but finite, size the properties of which are representative of larger region surrounding them. Consideration of the fluid elements of finite dimensions allows one to formulate a small scale mixing model with an explicit dependency on the molecular transport coefficients. The dimensions of a mesoscale element are determined from an evolution equation accounting for the molecular diffusion and the strain rate induced by small-scale turbulence while its position is determined by convection by large-scale velocity components. In addition to consideration of the fluid elements of a finite size, the second key new concept is the notion of radius of influence over which such an element contributes to the statistics of the flow; this radius grows with time. It is shown that the proposed method satisfies the mass conservation and normalisation of the probability density functions of scalar quantities. The proposed method is illustrated with simulations of thermal mixing layer in grid turbulence.

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Study of scalar macro- and microstructures in a confined jet

Cited by 13 publications

References 20 publications

Development of macro- and micromixing in confined flows of reactive fluids

Development of macro- and micromixing in confined flows of reactive fluids

Large eddy simulation of a coaxial jet with a synthetic turbulent inlet

Mesoscale elements description of turbulent flow

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