Effect on Richtmyer-Meshkov instability of deviation from sinusoidality of the corrugated interface between two fluids

Gupta, Manash Ranjan; Roy, Sunipa; Sarkar, Sourav; Khan, Manoranjan; Pant, H. C.; Srivastava, Mohit

doi:10.1017/s026303460700050x

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…Although the effect of initial perturbations (Erez et al 2000;Dimonte 2004;Greenough & Burke 2004;Gupta et al 2007) and incident Mach number (Samtaney & Zabusky 1993;Holmes et al 1999;Orlicz et al 2009) has been the subject of extensive research, the influence of the Atwood ratio has been little studied in the literature. Previous work has mainly focused on the nonlinear evolution of the two unstable fingering structure fronts in such flows, known as spikes and bubbles, for initially sharp multi-mode interfaces (when the intrinsic interface thickness is small compared with the perturbation amplitude), e.g.…”

Section: Introductionmentioning

confidence: 99%

Atwood ratio dependence of Richtmyer–Meshkov flows under reshock conditions using large-eddy simulations

et al. 2011

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We study the shock-driven turbulent mixing that occurs when a perturbed planar density interface is impacted by a planar shock wave of moderate strength and subsequently reshocked. The present work is a systematic study of the influence of the relative molecular weights of the gases in the form of the initial Atwood ratio A. We investigate the cases A = ± 0.21, ±0.67 and ±0.87 that correspond to the realistic gas combinations air-CO 2 , air-SF 6 and H 2 -air. A canonical, threedimensional numerical experiment, using the large-eddy simulation technique with an explicit subgrid model, reproduces the interaction within a shock tube with an endwall where the incident shock Mach number is ∼1.5 and the initial interface perturbation has a fixed dominant wavelength and a fixed amplitude-to-wavelength ratio ∼0.1. For positive Atwood configurations, the reshock is followed by secondary waves in the form of alternate expansion and compression waves travelling between the endwall and the mixing zone. These reverberations are shown to intensify turbulent kinetic energy and dissipation across the mixing zone. In contrast, negative Atwood number configurations produce multiple secondary reshocks following the primary reshock, and their effect on the mixing region is less pronounced. As the magnitude of A is increased, the mixing zone tends to evolve less symmetrically. The mixing zone growth rate following the primary reshock approaches a linear evolution prior to the secondary wave interactions. When considering the full range of examined Atwood numbers, measurements of this growth rate do not agree well with predictions of existing analytic reshock models such as the model by Mikaelian (Physica D, vol. 36, 1989, p. 343). Accordingly, we propose an empirical formula and also a semianalytical, impulsive model based on a diffuse-interface approach to describe the A-dependence of the post-reshock growth rate.

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Section: Introductionmentioning

confidence: 99%

Atwood ratio dependence of Richtmyer–Meshkov flows under reshock conditions using large-eddy simulations

et al. 2011

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“…Numerical,simulation and experimental results [26] − [29] of RMI are performed in cylindrical geometry considering implosion and explosion situation. However, the growth of RM instability can be suppressed due to different shape of the interface [30] − [31]. Recently, X-ray and proton radiography technique has been used to study the fast ignition implosion in cylindrical geometry [32] − [34].…”

Section: Introductionmentioning

confidence: 99%

Richtmyer - Meshkov instability in a spherical target with density variation

Mandal,

Roy,

Banerjee

et al. 2011

Preprint

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The motion of unstable fluid interface due to Richtmyer -Meshkov (RM) instability incorporating with density variation has been studied in a spherical target using Lagrangian formulation. During the compression in Inertial Confinement Fusion (ICF) process, the density of deuterium -tritium (DT) fuel increases 1000 times greater than the density of gaseous DT fuel within the core of spherical target. We have extended the feature of density variation [PRA,84-Mikaelian & Lindl] in spherical geometry.Due to convergent shock impingement, the perturbed interface will be nonspherical which leads to the density variation in both radial as well as in polar angle. We have shown that the interface of perturbed surface decreases with time to reach a minimum and then kick back to gradual increase. As the perturbed radius decreases, the density increases and reaches a maxima corresponding to a minima of perturbed radius. This is the practical situation of density characteristics during implosion of ICF. The numerical results based on our analytical work show a good qualitative agreement with some experimental as well as simulation results.

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Numerical investigation of magnetic Richtmyer-Meshkov instability

2012

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We report numerical results of the linear growth of the Richtmyer-Meshkov instability (RMI) in compressible fluids and in the presence of a magnetic field. These results are obtained with the Lagrangian code LPC-MHD in which media are supposed to be compressible ideal gases. We first applied a magnetic field perpendicular to the wave vector and perpendicular to the shock wave propagation and observed no changes on the perturbation growth velocity compared to the case without magnetic field. We also considered the configuration where the magnetic field is parallel to the wave vector. We observed the stabilization of the instability with oscillations of the perturbations amplitude. Numerical results are compared to impulsive acceleration model of the RMI in the presence of a transverse magnetic field, in the non-compressible limit. A good agreement is obtained between numerical results and model for both the amplitude and the frequency of oscillations. Compressibility seems to have negligible effects.

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Effect on Richtmyer-Meshkov instability of deviation from sinusoidality of the corrugated interface between two fluids

Cited by 3 publications

References 9 publications

Atwood ratio dependence of Richtmyer–Meshkov flows under reshock conditions using large-eddy simulations

Atwood ratio dependence of Richtmyer–Meshkov flows under reshock conditions using large-eddy simulations

Richtmyer - Meshkov instability in a spherical target with density variation

Numerical investigation of magnetic Richtmyer-Meshkov instability

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