Experiments of the Richtmyer–Meshkov instability

Abstract

The Richtmyer–Meshkov instability is caused by a shock interacting with a density-stratified interface. The mixing of the fluids is driven by vorticity created by the interaction of the density and pressure gradients. Because the flow is shock driven, the ensuing mixing occurs rapidly, making experimental measurements difficult. Over the past 10 years, there have been significant improvements in the experimental techniques used in shock-driven mixing flows. Many of these improvements have been driven by modelling and simulation efforts, and others have been driven by technology. High-resolution measurements of turbulence quantities are needed to advance our understanding of shock-driven flows, and this paper reviews the current state of experimental diagnostics, as well as paths forward in studying shock-driven mixing and turbulence.

Density and velocity statistics in variable density turbulent mixing

“…[12][13][14][15] RM instability has been studied for many years, [16][17][18][19] with recent emphasis on the subsequent turbulent mixing in a RM unstable fluid layer. [20][21][22] These studies show that variations in the initial conditions and Mach number lead to different flow features, turbulence statistics, and material mixing.…”

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

“…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]. Depending on the circumstances, homogeneous turbulence in mixing layers can be modulated at large scales [111] and can exhibit structures (the so-called 'plumes') with superimposed small-scale mixing, in agreement with experiments [112].…”

Turbulent mixing and beyond: non-equilibrium processes from atomistic to astrophysical scales II

“…This part II of the Theme Issue consists of the following papers: the paper by Sreenivasan & Abarzhi on acceleration and turbulence in Rayleigh-Taylor (RT) mixing [1]; by Meshkov on experimental studies of unstable interfaces [2]; by Youngs on numerical modelling simulations of self-similar regimes in mixing flows [3]; by Grinstein et al [4] on a pragmatic approach for reproducing complex multiphase flows in simulations; by Glimm et al [5] on the so-called alpha problem; by Nevmerzhitskiy on the implementation and diagnostics of RT/Richtmyer-Meshkov (RM) mixing in experiments [6]; by Livescu on high resolution approaches for numerical modelling of RT instabilities [7]; by Statsenko et al [8] on subgrid scale models applied to RT/RM mixing; by Prestridge et al analysing the RM mixing experiments conducted over the past decade [9]; by Levitas on mixing applications in reactive flows [10]; by Pudritz & Kevlahan on supersonic processes and shock waves in interstellar media [11]; and by Anisimov et al [12] summarizing the status of our understanding of RT mixing. We observe the development of the Rayleigh-Taylor instability (RTI) when fluids of different densities are accelerated against the density gradient [13,14].…”

“…Prestridge et al [9] review and analyse the RM experiments carried out over the last decade and focus on the influence of shock strength, density contrast, initial conditions, and threedimensional effects on flow evolution. The authors confirm that the width of the mixing zone scales with the Mach number.…”