Observation of mix in a compressible plasma in a convergent cylindrical geometry

Barnes, Cris W.; Batha, S. H.; Dunne, Mike; Magelssen, G. R.; Rothman, S. D.; Day, R. D.; Elliott, N.; Haynes, D. A.; Holmes, Richard; Scott, J. M.; Tubbs, D. L.; Youngs, D. L.; Boehly, T. R.; Jaanimagi, P. A.

doi:10.1063/1.1511730

Cited by 50 publications

(20 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The broadband simulation employs a perturbation spectrum typical of the finish of an ICF capsule, where P k ð Þ / k À2 . 23 The aim is to study the growth rate in isolation of other fluid dynamic phenomena experienced within the shock-tube experiments, for example, reflected rarefaction waves. Hence, the two shocks are generated numerically within the computational domain with nonreflective boundary conditions to allow the reflected shock/ expansions to exit the domain unimpeded.…”

Section: Introductionmentioning

confidence: 99%

Growth of a Richtmyer-Meshkov turbulent layer after reshock

et al. 2011

Self Cite

View full text Add to dashboard Cite

This paper presents a numerical study of a reshocked turbulent mixing layer using high-order accurate Implicit Large-Eddy-Simulations (ILES). Existing theoretical approaches are discussed, and the theory of Youngs (detailed in Ref. 1) is extended to predict the behaviour of a reshocked mixing layer formed initially from a shock interacting with a broadband instability. The theory of Mikaelian2 is also extended to account for molecular mixing in the single-shocked layer prior to reshock. Simulations are conducted for broadband and narrowband initial perturbations and results for the growth rate of the reshocked layer and the decay rate of turbulent kinetic energy show excellent agreement with the extended theoretical approach. Reshock causes a marginal decrease in mixing parameters for the narrowband layer, but a significant increase for the broadband initial perturbation. The layer properties are observed to be very similar post-reshock, however, the growth rate exponent for the mixing layer width is higher in the broadband case, indicating that the reshocked layer still has a dependence (although weakened) on the initial conditions. These results have important implications for Unsteady Reynolds Averaged Navier Stokes modelling of such instabilities.

show abstract

Section: Introductionmentioning

confidence: 99%

Growth of a Richtmyer-Meshkov turbulent layer after reshock

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…Calculation 12 at ρ 1 /ρ 2 = 3 was a repeat of calculation 8 with the power spectrum changed to P(k) ∼ k −2 while keeping σ the same. A k −2 spectrum is more typical of some practical applications, for example Barnes et al [32], and was chosen to see whether the change in spectrum altered the selfsimilar properties. The change in spectrum gave a slight reduction in α and a slightly greater reduction in α towards the end of simulation.…”

Section: The Current Series Of High-resolution Rayleigh-taylor Simulamentioning

confidence: 99%

The density ratio dependence of self-similar Rayleigh–Taylor mixing

Youngs

2013

Phil. Trans. R. Soc. A.

107

View full text Add to dashboard Cite

Previous research on self-similar mixing caused by Rayleigh–Taylor (RT) instability is summarized and a recent series of high resolution large eddy simulations is described. Mesh sizes of approximately 2000 ×1000 × 1000 are used to investigate the properties of high Reynolds number self-similar RT mixing at a range of density ratios from 1.5 : 1 to 20 : 1. In some cases, mixing evolves from ‘small random perturbations’. In other cases, random long wavelength perturbations ( k −3 spectrum) are added to give self-similar mixing at an enhanced rate, more typical of that observed in experiments. The properties of the turbulent mixing zone (volume fraction distributions, turbulence kinetic energy, molecular mixing parameter, etc.) are related to the RT growth rate parameter, α . Comparisons are made with experimental data on the internal structure and the asymmetry of the mixing zone (spike distance/bubble distance). The main purpose of this series of simulations is to provide data for calibration of engineering models (e.g. Reynolds-averaged Navier–Stokes models). It is argued that the influence of initial conditions is likely to be significant in most applications and the implications of this for engineering modelling are discussed.

show abstract

“…We note a strong time dependence for the relative spectral amplitudes, with A 2 ∼ k 0 at the early time (third plate) plot, and the fraction of long wave spectral energy dropping from 50% to 80% initially to about 2% at the time of the third plate. k −2 and k −3/2 A 2 initial spectra have been observed in the machined surfaces present in plasma experiments [14]. The second purpose of this paper is to develop a plan for use of experimental data in simulation initialization.…”

Section: Introductionmentioning

confidence: 99%