High-Reynolds number Rayleigh–Taylor turbulence

Livescu, Daniel; Ristorcelli, J. R.; Gore, Robert; Dean, Sumner; Cabot, W.; Cook, Andrew W.

doi:10.1080/14685240902870448

Cited by 95 publications

(140 citation statements)

References 15 publications

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“…That the anisotropy increases with wavenumber is perhaps counterintuitive, and perhaps contradictory to the notion of small-scale isotropy. This was first pointed out by Livescu & Ristorcelli (2008) and further discussed by Livescu et al (2009 (no summation), but found that, with this measure, the small scales were isotropic. A question then arises as to why the velocity-anisotropy parameter increases in the viscosity-dominated range 10 −1 < k r η < 2.…”

Section: Subgrid Extensions Of Planar Spectramentioning

confidence: 80%

Direct numerical simulation and large-eddy simulation of stationary buoyancy-driven turbulence

Chung

Pullin

2009

J. Fluid Mech.

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We report direct numerical simulation (DNS) and large-eddy simulation (LES) of statistically stationary buoyancy-driven turbulent mixing of an active scalar. We use an adaptation of the fringe-region technique, which continually supplies the flow with unmixed fluids at two opposite faces of a triply periodic domain in the presence of gravity, effectively maintaining an unstably stratified, but statistically stationary flow. We also develop a new method to solve the governing equations, based on the Helmholtz-Hodge decomposition, that guarantees discrete mass conservation regardless of iteration errors. Whilst some statistics were found to be sensitive to the computational box size, we show, from inner-scaled planar spectra, that the small scales exhibit similarity independent of Reynolds number, density ratio and aspect ratio. We also perform LES of the present flow using the stretched-vortex subgridscale (SGS) model. The utility of an SGS scalar flux closure for passive scalars is demonstrated in the present active-scalar, stably stratified flow setting. The multi-scale character of the stretched-vortex SGS model is shown to enable extension of some second-order statistics to subgrid scales. Comparisons with DNS velocity spectra and velocity-density cospectra show that both the resolved-scale and SGS-extended components of the LES spectra accurately capture important features of the DNS spectra, including small-scale anisotropy and the shape of the viscous roll-off.

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Section: Subgrid Extensions Of Planar Spectramentioning

confidence: 80%

Direct numerical simulation and large-eddy simulation of stationary buoyancy-driven turbulence

Chung

Pullin

2009

J. Fluid Mech.

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“…In situations where the KE changes rapidly, the dissipation rate lags behind the cascade rate given by u 3 /Λ due to the time needed to redistribute the KE over the inertial range (Livescu et al 2009). …”

Section: Kinetic Energy Dampingmentioning

confidence: 99%

Turbulent Convection in Stellar Interiors. Iii. Mean-Field Analysis and Stratification Effects

Viallet

Meakin

Arnett

et al. 2013

ApJ

126

213

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We present three-dimensional implicit large eddy simulations of the turbulent convection in the envelope of a 5 M red giant star and in the oxygen-burning shell of a 23 M supernova progenitor. The numerical models are analyzed in the framework of one-dimensional Reynolds-Averaged Navier-Stokes equations. The effects of pressure fluctuations are more important in the red giant model, owing to larger stratification of the convective zone. We show how this impacts different terms in the mean-field equations. We clarify the driving sources of kinetic energy, and show that the rate of turbulent dissipation is comparable to the convective luminosity. Although our flows have low Mach numbers and are nearly adiabatic, our analysis is general and can be applied to photospheric convection as well. The robustness of our analysis of turbulent convection is supported by the insensitivity of the mean-field balances to linear mesh resolution. We find robust results for the turbulent convection zone and the stable layers in the oxygen-burning shell model, and robust results everywhere in the red giant model, but the mean fields are not well converged in the narrow boundary regions (which contain steep gradients) in the oxygen-burning shell model. This last result illustrates the importance of unresolved physics at the convective boundary, which governs the mixing there.

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“…As far as we know, there are no exhaustive detailed calculations of the stability problem for such configuration, even though not too different from the usual RT compressible case [50,66,67]. As said, this is not the common way to study RT systems, which is usually meant as the superposition of two different miscible fluids, isothermal, with different densities [50,61,66,68]. As far as compressible effects are small, one may safely neglect pressure fluctuations and write -for the case of an ideal gas:…”

Section: Rayleigh-taylor Systemsmentioning

confidence: 99%

“…Although this instability was studied for decades it is still an open problem in several aspects [60]. In particular, it is crucial to control the initial and late evolution of the mixing layer between the two miscible fluids; the small-scale turbulent fluctuations, their anisotropic/isotropic ratio; their dependency on the initial perturbation spectrum or on the physical dimensions of the embedding space [61,62]. In many cases, especially concerning astrophysical and nuclear applications, the two fluids evolve with strong compressible and/or stratification effects, a situation which is difficult to investigate either theoretically or numerically.…”

Section: Rayleigh-taylor Systemsmentioning

confidence: 99%

Lattice Boltzmann methods for thermal flows: Continuum limit and applications to compressible Rayleigh–Taylor systems

Scagliarini¹,

Biferale²,

Sbragaglia

et al. 2010

Physics of Fluids

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We compute the continuum thermo-hydrodynamical limit of a new formulation of lattice kinetic equations for thermal compressible flows, recently proposed in [Sbragaglia et al., J. Fluid Mech. 628 299 (2009)]. We show that the hydrodynamical manifold is given by the correct compressible FourierNavier-Stokes equations for a perfect fluid. We validate the numerical algorithm by means of exact results for transition to convection in Rayleigh-Bénard compressible systems and against direct comparison with finite-difference schemes. The method is stable and reliable up to temperature jumps between top and bottom walls of the order of 50% the averaged bulk temperature. We use this method to study Rayleigh-Taylor instability for compressible stratified flows and we determine the growth of the mixing layer at changing Atwood numbers up to At ∼ 0.4. We highlight the role played by the adiabatic gradient in stopping the mixing layer growth in presence of high stratification and we quantify the asymmetric growth rate for spikes and bubbles for two dimensional RayleighTaylor systems with resolution up to Lx × Lz = 1664 × 4400 and with Rayleigh numbers up to Ra ∼ 2 × 10 10 .

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High-Reynolds number Rayleigh–Taylor turbulence

Cited by 95 publications

References 15 publications

Direct numerical simulation and large-eddy simulation of stationary buoyancy-driven turbulence

Direct numerical simulation and large-eddy simulation of stationary buoyancy-driven turbulence

Turbulent Convection in Stellar Interiors. Iii. Mean-Field Analysis and Stratification Effects

Lattice Boltzmann methods for thermal flows: Continuum limit and applications to compressible Rayleigh–Taylor systems

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