A second-order turbulence model for gaseous mixtures induced by Richtmyer—Meshkov instability

Grégoire, Olivier; Souffland, D.; Gauthier, Serge

doi:10.1080/14685240500307413

Cited by 63 publications

(36 citation statements)

References 29 publications

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“…For whatever reasons, a brief literature survey reveals that a large number of multicomponent NavierStokes simulations omit the enthalpy diffusion term in the energy equation. [21][22][23][24][25][26][27][28][29][30] Here we refer to a Navier-Stokes simulation as any solver that includes viscous, conductive, and diffusive terms, even if those terms represent turbulence models, rather than molecular processes. The primary objective of this paper is to demonstrate some of the errors that can result from neglecting the enthalpy diffusion term and identify some situations in which the term is critically important.…”

Section: Introductionmentioning

confidence: 99%

Enthalpy diffusion in multicomponent flows

Cook

2009

Physics of Fluids

123

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The enthalpy diffusion flux in the multicomponent energy equation is a well-known yet frequently neglected term. It accounts for energy changes associated with compositional changes resulting from species diffusion. The term prevents local violations of the entropy condition in flows where significant mixing occurs between species of dissimilar molecular weight. In simulations of nonpremixed combustion, omission of the enthalpy flux can lead to anomalous temperature gradients, which may cause mixing regions to exceed ignition conditions. The term can also play a role in generating acoustic noise in turbulent mixing layers. Euler solvers that rely on numerical diffusion to blend fluids at the grid scale cannot reliably predict temperatures in mixing regions. On the other hand, Navier-Stokes solvers that incorporate enthalpy diffusion can provide much more accurate results. In constructing turbulence closures for high Reynolds number mixing, the same turbulent diffusion model that appears in the species mass transport equation should also appear in the energy equation as part of a "turbulent enthalpy diffusion;" otherwise the energy and species transport equations will not be consistent.

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Section: Introductionmentioning

confidence: 99%

Enthalpy diffusion in multicomponent flows

Cook

2009

Physics of Fluids

123

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“…These models were extensively validated against experiments and served as research tools, for instance, by bringing some insight into the time dependence and magnitude of turbulent kinetic energy [86,98] and the Reynolds stress anisotropy [105,106,108]. The numerical models found the development of homogeneous turbulence in RT mixing layers in the case of miscible fluids with seeded small-scale initial perturbations, as well as in Richtmyer-Meshkov flows (that can be interpreted as RT flow with impulsive acceleration) [109,110].…”

Section: (I) Interpolation and Turbulence Modelsmentioning

confidence: 99%

“…In the past 50 years, a broad variety of numerical models were developed for implementation and modelling of turbulence in RT mixing [41][42][43]67,68,85,86,98,[100][101][102][103][104][105][106][107][108]. These models were extensively validated against experiments and served as research tools, for instance, by bringing some insight into the time dependence and magnitude of turbulent kinetic energy [86,98] and the Reynolds stress anisotropy [105,106,108].…”

Section: (I) Interpolation and Turbulence Modelsmentioning

confidence: 99%

What is certain and what is not so certain in our knowledge of Rayleigh–Taylor mixing?

Anisimov

Drake

Gauthier

et al. 2013

Phil. Trans. R. Soc. A.

Self Cite

180

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“…In a heuristic sense b plays the role of the concentration variance in buoyantly driven flows in the Boussinesq approximation, when ρ ρ (Launder 1989); in this case 294 C. D. Tomkins, B. J. Balakumar, G. Orlicz, K. P. Prestridge and J. R. Ristorcelli which is an approximation used in some second-order closures (e.g. Gregoire, Souffland & Gauthier 2005). As initially shown by and further discussed by Schwarzkopf et al (2011), however, using the explicit transport equation for ρv as a closure for VD flows captures important physics, particularly in regimes away from the Boussinesq approximation.…”

Section: Planar Density and Velocity Measurementsmentioning

confidence: 99%

Evolution of the density self-correlation in developing Richtmyer–Meshkov turbulence

et al. 2013

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Turbulent mixing in a Richtmyer-Meshkov unstable light-heavy-light (air-SF 6 -air) fluid layer subjected to a shock (Mach 1.20) and a reshock (Mach 1.14) is investigated using ensemble statistics obtained from simultaneous velocity-density measurements. The mixing is driven by an unstable array of initially symmetric vortices that induce rapid material mixing and create smaller-scale vortices. After reshock the flow appears to transition to a turbulent (likely three-dimensional) state, at which time our planar measurements are used to probe the developing flow field. The density selfcorrelation b = − ρv (where ρ and v are the fluctuating density and specific volume, respectively) and terms in its evolution equation are directly measured experimentally for the first time. Amongst other things, it is found that production terms in the b equation are balanced by the dissipation terms, suggesting a form of equilibrium in b. Simultaneous velocity measurements are used to probe the state of the incipient turbulence. A length-scale analysis suggests that an inertial range is beginning to form, consistent with the onset of a mixing transition. The developing turbulence is observed to reduce non-Boussinesq effects in the flow, which are found to be small over much of the layer after reshock. Second-order two-point structure functions of the density field exhibit a power-law behaviour with a steeper exponent than the standard 2/3 power found in canonical turbulence. The absence of a significant 2/3 region is observed to be consistent with the state of the flow, and the emergence of the steeper power-law region is discussed.

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A second-order turbulence model for gaseous mixtures induced by Richtmyer—Meshkov instability

Cited by 63 publications

References 29 publications

Enthalpy diffusion in multicomponent flows

Enthalpy diffusion in multicomponent flows

What is certain and what is not so certain in our knowledge of Rayleigh–Taylor mixing?

Evolution of the density self-correlation in developing Richtmyer–Meshkov turbulence

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