Experiments on the Richtmyer-Meshkov instability of an air/SF 6 interface
TL;DR: In this article, the authors performed flow visualization experiments of an impulsively accelerated plane interface between air and SF6 and found that the thin membrane, which forms the initially plane interface, has a significant influence on the initial growth rate of the interface thickness.
Abstract: Results of flow visualization experiments of an impulsively accelerated plane interface between air and SF6 are reported. The shock tube used for the experiments has a larger test section than in previous experiments. The larger extent of uniform test flow relative to nonuniform boundary-layer flow permits unambiguous interpretation of flow-visualization photographs, and the influence of shock-wave/boundary-layer interactions is no longer dominant. The strong wall vortex observed in previous studies is not observed in these experiments. It is found that the thin membrane, which forms the initially plane interface, has a significant influence on the initial growth rate of the interface thickness. However, the measured growth rates after the first reflected shock are independent of membrane configuration and are in good agreement with analytical predictions.
Citations
More filters
TL;DR: In this article, Zhou et al. presented the initial condition dependence of Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) mixing layers, and introduced parameters that are used to evaluate the level of mixedness and mixed mass within the layers.
606 citations
TL;DR: In this paper, a shock-capturing approach to multicomponent flow problems is developed for the compressible Euler equations with a stiffened gas equation of state in multiple space dimensions.
361 citations
Additional excerpts
...developed by Zhang and Sohn [76] and the laboratory experiments [27, 73 ] will be reported elsewhere [66]....
[...]
TL;DR: In this article, the turbulent Rayleigh-Taylor instability was investigated over a comprehensive range of fluid density ratio (R)1.3⩽R50 [0.96] and different acceleration histories g(t) using the Linear Electric Motor.
Abstract: The turbulent Rayleigh–Taylor instability is investigated over a comprehensive range of fluid density ratio (R)1.3⩽R⩽50 [0.15⩽A=(R−1)/(R+1)⩽0.96] and different acceleration histories g(t) using the Linear Electric Motor. The mixing layer is diagnosed with backlit photography and laser-induced fluorescence. For a constant acceleration, the bubble (2) and spike (1) amplitudes are found to increase as hi=αiAgt2 with α2∼0.05±0.005 and α1∼α2RDα with Dα∼0.33±0.05. For temporally varying accelerations Ag(t)>0, this can be generalized to hi=2αiAS using S=[∫gdt]2/2 rather than the displacement Z=∫∫gdt′ dt. For impulsive accelerations, S remains constant during the coast phase and the amplitudes obey a power law hi∼tθi with θ2∼0.25±0.05 and θ1∼θ2RDθ with Dθ∼0.21±0.05. These values of Dα and Dθ compare favorably with numerical simulations and mix models. The average diameter at the mixing front for bubbles is found to increase as d2∼h2(1+A)/4 in qualitative agreement with “merger” models, but the associated dhi/dt i...
351 citations
TL;DR: In this paper, the authors investigated the Richtmyer-Meshkov instability for negative Atwood number and two-dimensional sinusoidal perturbations by comparing experiments, numerical simulations and analytic theories.
Abstract: Richtmyer–Meshkov instability is investigated for negative Atwood number and two-dimensional sinusoidal perturbations by comparing experiments, numerical simulations and analytic theories. The experiments were conducted on the NOVA laser with strong radiatively driven shocks with Mach numbers greater than 10. Three different hydrodynamics codes (RAGE, PROMETHEUS and FronTier) reproduce the amplitude evolution and the gross features in the experiment while the fine-scale features differ in the different numerical techniques. Linearized theories correctly calculate the growth rates at small amplitude and early time, but fail at large amplitude and late time. A nonlinear theory using asymptotic matching between the linear theory and a potential flow model shows much better agreement with the late-time and large-amplitude growth rates found in the experiments and simulations. We vary the incident shock strength and initial perturbation amplitude to study the behaviour of the simulations and theory and to study the effects of compression and nonlinearity.
247 citations
Additional excerpts
...…between experimentally measured and predicted growth rates has been attributed to strength and porosity effects of the membrane used to separate the gases in shock tube experiments (Cloutman & Wehner 1992; Meshkov 1970; Meyer & Blewett 1972) and boundary layer effects (Vetter & Sturtevant 1995)....
[...]
TL;DR: In this paper, large-eddy simulations of the Richtmyer-Meshkov instability with reshock are pre- sented and the results are compared with experiments, where statistics of the unresolved scales of the flow are estimated.
Abstract: Large-eddy simulations of the Richtmyer–Meshkov instability with reshock are pre- sented and the results are compared with experiments. Several configurations of shocks initially travelling from light (air) to heavy (sulfur hexafluoride, SF6) have been simulated to match previous experiments and good agreement is found in the growth rates of the turbulent mixing zone (TMZ). The stretched-vortex subgrid model used in this study allows for subgrid continuation modelling, where statistics of the unresolved scales of the flow are estimated. In particular, this multiscale modelling allows the anisotropy of the flow to be extended to the dissipation scale, eta, and estimates to be formed for the subgrid probability density function of the mixture fraction of air/SF6 based on the subgrid variance, including the effect of Schmidt number.
211 citations
Cites background or methods or result from "Experiments on the Richtmyer-Meshko..."
...Figure 5 shows the computed mixing width for the higher resolution Mach 1.50 run where the experimentally measured growth rates of Vetter & Sturtevant (1995) are also indicated....
[...]
... Vetter & Sturtevant (1995) measured the instantaneous width of the mixing zone and calculated two mixing-zone growth rates, one after the initial shock and a second following reshock, for each experiment....
[...]
...The much better agreement after reshock is consistent with the detailed Mach 1.50 experiment of Vetter & Sturtevant (1995) (summarized in their figure 8) in which the initial conditions were varied by altering the membrane and wire mesh configuration....
[...]
...Meshkov instability realized within the confines of a shock-tube as a planar shock interacts with a co-planar density interface formed by the contact between two gases, air and sulfur hexafluoride (SH6) ( Vetter & Sturtevant 1995 )....
[...]
... Vetter & Sturtevant (1995) indicate that a relatively weak expansion wave from the driver section of the shock tube follows, 0.5 ms in the Mach 1.5 case, after the shock....
[...]
References
More filters
1,696 citations
TL;DR: In this paper, an experimental study of the stability of the interface of two gases traversed by ash-wave was conducted and it was found that the interface is unstable both in the case of shock wave passage from the lighter to the heavier gas and for passage in the opposite direction.
Abstract: Results are presented of an experimental study of the stability of the interface of two gases traversed by ashockwave. It is found that the interface is unstable both in the case of shock wave passage from the lighter to the heavier gas and for passage in the opposite direction. The interface disturbance grows linearly with time in the first approximation.
1,168 citations
TL;DR: A novel experimental technique using solid fuel rocket motors has been developed at AWRE Foulness to study the growth of Rayleigh-Taylor instabilities in fluids as mentioned in this paper, which achieves near constant acceleration up to 750 m s-2 over distances of 1.25 m.
524 citations
TL;DR: In this article, a form of turbulence model based on the equations of multiphase flow is proposed to describe velocity separation arising from the action of a pressure gradient on fluid fragments of different density.
238 citations
TL;DR: In this paper, the authors apply the Canuto-Goldman (CG) analytical model to turbulence generated by the class of instabilities which have a power-law growth rate, based on the experiments of Read and Youngs.
124 citations