Turbulence topology evolution in weakly turbulent premixed flames

Mura, Arnaud; Zhao, Song

doi:10.1063/5.0039330

Cited by 7 publications

(1 citation statement)

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“…This enthusiastic response is another indication of the respect Ted O'Brien has within the international research community of turbulence and reactive flows. These contributions are on diverse topics including combustion instability, 150,151 scalar mixing, [152][153][154][155][156] homogeneous isotropic turbulence, [157][158][159][160] turbulent premixed flames, [161][162][163][164][165][166][167][168][169][170][171] turbulent non-premixed flames, [172][173][174][175] wallbounded turbulence, [176][177][178] turbulent combustion modeling, [179][180][181] FDF/PDF, [182][183][184][185][186][187][188][189][190][191][192] and two-phase turbulent flows. [193][194][195][196]<...…”

Section: Organization Of This Simentioning

confidence: 99%

Edward E. O'Brien contributions to reactive-flow turbulence

2021

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Professor Edward Ephraim O'Brien ("Ted") has made lasting contributions to the theory and modeling of scalar mixing and reaction in turbulent flows. With a doctoral dissertation at The Johns Hopkins University in 1960, entitled "On the Statistical Behavior of a Dilute Reactant in Isotropic Turbulence," supervised by the legend Stanley Corrsin, and in the company of notable pioneer of turbulence, John Leask Lumley, Ted's academic training propelled him through a prolific career. In the opening article of this Special Issue, we provide a review of some of Ted's contributions. First, a summary is presented of his work on the examination of the failure of the cumulant discard approximation for the scalar mixing. This is followed by a highlight of his impacts on other spectral theories of turbulence including Kraichnan's direct interaction approximation. His contributions to more modern theoretical/computational description of reactive turbulence are discussed next, including the transported probability density function (pdf) formulation, scalar-gradient pdf transport equation, scalar interfaces, and the filtered density function. Finally, some of his research on Direct Numerical Simulation of compressible turbulence is reviewed.

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Section: Organization Of This Simentioning

confidence: 99%

Edward E. O'Brien contributions to reactive-flow turbulence

2021

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A model problem for the evolution of strain structure at the crossing of a flame front

Gonzalez

2022

Theor. Comput. Fluid Dyn.

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The local thermal effect of a flame front is simulated by a model for a mass density front by specifying a likely expansion rate. This model problem includes two independent parameters, namely the heat release parameter and a parameter akin to a Karlovitz number. The analysis is focused on the influence of the Karlovitz number on the evolution of strain properties at the crossing of the front. The latter are derived from an equation system for the velocity gradient tensor and the pressure Hessian tensor undergoing the forcing of the expansion rate. Strain eigenvalues, orientation of strain principal axes, and stretching in the direction of forcing are especially scrutinized. Furthermore, the model shows that, when approaching a flame front, the special alignments of strain are mostly caused by anisotropy of pressure Hessian resulting from forcing by expansion. KeywordsVelocity gradient • Strain structure • Premixed flames • Variable mass density • Pressure Hessian 1 IntroductionMicromixing is the mere expression of the small-scale action of flow on scalar fields, more precisely, the outcome of the mechanical action exerted by the velocity gradient on the gradients of scalars. The straining part of the velocity gradient, at least in incompressible flows, tends to enhance scalar gradients through compression, thereby hastening local diffusive fluxes. Thus the level of micromixing tightly depends on strain main properties, namely intensity, direction, and lifetime.Mixing in non-solenoidal flows is a special case, for mass density variations may deeply affect the velocity gradient. Alteration of the intensity and/or orientation of strain, then, may influence the micromixing process. This is especially relevant in compressible flows [1,2] and in reacting flows with heat release such as flames [3][4][5][6][7][8][9]. More specifically, scalar dissipation -the key mechanism driving

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