Investigation of interaction between reflected shocks and growing perturbation on an interface

Chebotareva, E. I.; Алешин, А. Н.; Zaytsev, S. G.; Сергеев, С. В.

doi:10.1007/s001930050142

Cited by 5 publications

(4 citation statements)

References 2 publications

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“…The nonlinear RM flow is characterized by the large-scale structure, small-scale structures, and energy transport between the large and small scales (Chebotareva et al 1999;Collins & Jacobs 2002;Jacobs & Krivets 2005;Zabusky et al 2003). The large-scale structure is coherent and this is an array of bubble and spikes, characterized by the period λ and the position h of the bubble or spike.…”

Section: Theorymentioning

confidence: 99%

“…The small-scale vortical structures are driven by shear, and their dynamics is in general non-deterministics (Frisch 1995) and is not defined uniquelly by the initial conditions. According to observations (Chebotareva et al 1999;Collins & Jacobs 2002;Jacobs & Krivets 2005), for fluids with contrasting densities the scales can be separated, and the large-scale coherent motion can be regarded as irrotational, with ∇×v h(l) = 0. The idea of separation in the RT/RM unstable flows of the large-scale structure, which is "passively advected", from the small-scale structures, which are "active" and characterized by intense vorticity, was suggested first by Aref & Tryggvason (1989) and then developed by Abarzhi (2001), and Abarzhi et al (2003).…”

Section: Theorymentioning

confidence: 99%

“…In the nonlinear regime, the growth rate decreases, and the coherent structure of bubbles and spikes appears (Aleshin, Ganalii & Zaitsev 1988;Aleshin, Lazareva & Zaitsev 1990). The light (heavy) fluid penetrates the heavy (light) fluid in bubbles (spikes) and the spatial period of the structure is set either by the initial conditions or by the mode of fastest growth (Collins & Jacobs 2002;Chebotareva et al 1999). Shear-driven instabilities create small-scale structures on the side of the evolving spikes (Matsuoka, Nishihara & Fukuda 2003;Zabusky et al 2003;Jacobs & Krivets 2005).…”

Section: Introductionmentioning

confidence: 99%

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Nonlinear evolution of the Richtmyer–Meshkov instability

2008

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We report analytical and numerical results describing the dynamics of the two-dimensional coherent structure of bubbles and spikes in the Richtmyer–Meshkov instability for fluids with a finite density ratio. The theory accounts for the non-local properties of the interface evolution, and the simulations treat the interface as a discontinuity. Good agreement between the analytical and numerical results is achieved. To quantify accurately the interface dynamics in the simulations, new diagnostics and scalings are suggested. The velocity at which the interface would move if it were ideally planar is used to set the flow time scale as well as the reference point for the bubble (spike) position. The data sampling has high temporal resolution and captures the velocity oscillations caused by sound waves. The bubble velocity and curvature are both monitored, and the bubble curvature is shown to be the relevant diagnostic parameter. According to the results obtained, in the nonlinear regime of the Richtmyer–Meshkov instability the bubbles flatten and decelerate, and the flattening of the bubble front indicates the multiscale character of the coherent dynamics.

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Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nonlinear evolution of the Richtmyer–Meshkov instability

2008

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“…the interaction of shock waves with gas-inhomogeneities (6,18) . In the present case, the interest to study the flow instability stems both from the fundamental and the application point of view.…”

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confidence: 99%

Shock-wave induced instability in internal explosion dynamics

Bagabir

Drikakis

2005

Aeronaut. j.

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The study of non-stationary flows featuring shock waves is motivated by the need to understand the physics of shock wave phenomena, as well as by the variety of applications in which shock waves appear spanning from engineering to astrophysics. In the case of shock (blast) wave propagation in an enclosure the interest stems from explosion dynamics which arises from the very sudden release of chemical, nuclear, electrical or mechanical energy in a limited space.Even though past studies have investigated instabilities occurring when two fluids of different densities are impulsively accelerated into each other by a shock wave, known as Richtmyer-Meshkov (or impulsive Rayleigh-Taylor) instability (6,18) , the investigation of flow instabilities arising from the interaction of blast waves with a solid structure has received scarce attention. Flow instabilities have been experimentally detected in the case of cylindrical blast waves (7,14) . Burrows and Fryxell (1992) (5) have also shown that instabilities can occur in the mantles of nascent neutron stars implying that the standard spherically symmetric models of neutron star birth and supernova explosion may be inadequate. The above findings follow earlier analytical work (4) regarding the formation of convective ABSTRACT The paper presents an investigation of flow instabilities occurring in shock-wave propagation and interaction with the walls of an enclosure. The shock-wave propagation is studied in connection with perturbed and unperturbed cylindrical blasts, initially placed in the centre of the enclosure, as well as for three different blast intensities corresponding to Mach numbers M s = 2, 5 and 10. The instability is manifested by a symmetry-breaking of the flow even for the case of an initially perfectly-symmetric blast. It is shown that the symmetry-breaking initiates around the centre of the enclosure as a result of the interaction of the shock waves reflected from the walls, with the low-density region in the centre of the explosion. The instability leads to fast attenuation of the shock waves, especially for smaller initial blast intensities. The computations reveal that the vortical flow structures arising from the multiple shock reflections and flow instability are Mach number dependent. The existence of perturbations of large amplitude in the initial condition strengthens the instability and has significant effects on the instantaneous wall pressure distributions. The computational investigation has been performed using high-resolution Riemann solvers for the gas dynamic equations.

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