A semi-annular shock tube for studying cylindrically converging Richtmyer-Meshkov instability

Abstract

A novel semi-annular shock tube is realized by combining the advantageous features of two types of existing facilities for generating cylindrically converging shock waves. A high-speed schlieren photography is used to acquire the variation of shock positions versus the time and the evolution of a single-mode gaseous interface subjected to the cylindrical shock. The first experimental results indicate that the semi-annular configuration brings great convenience for interface formation and flow visualization, and the new facility has great potential for cylindrically converging Richtmyer-Meshkov instability studies.

On divergent Richtmyer–Meshkov instability of a light/heavy interface

“…As shown in figure 4, there exists only a minor difference between the linear and nonlinear predictions even at very late stages, which indicates a very weak nonlinearity for the divergent RMI. This finding is completely different from that of convergent RMI where nonlinearity is found to be strong and behaves evidently (Wang et al 2015;Luo et al 2019). The growth of the third harmonic together with its feedback to the primary mode, predicted by the nonlinear model of Wang et al (2015), is also shown in figure 4 (the growth of the second harmonic produces no influence on the whole perturbation growth and is not given).…”

“…The growth of the third harmonic together with its feedback to the primary mode, predicted by the nonlinear model of Wang et al (2015), is also shown in figure 4 (the growth of the second harmonic produces no influence on the whole perturbation growth and is not given). It is found that at early stages the growth of the third harmonic in divergent geometry is much smaller than that in a planar or convergent geometry (Luo et al 2019), which provides a further demonstration of weak nonlinearity. Although nonlinearity increases at late stages, the positive growth of the third harmonic approximately counteracts its negative feedback to the basic mode, which suggests a negligible influence of nonlinearity on the growth of overall perturbation amplitude.…”

“…It was observed that the perturbation amplitude presents a long-term linear growth with time, which was later carefully explained by Vandenboomgaerde et al (2018) through theoretical analysis and numerical simulation. Recently, the growth of a sinusoidal air-SF 6 interface subjected to a cylindrically convergent shock was measured in a semiannular shock tube (Luo et al 2015;Ding et al 2017), and the influences of the geometric convergence and RT stability on the perturbation growth were first quantified in experiments. The above studies demonstrated that the contraction of the flow cross-section brings additional physical regimes and hence greatly affects the instability growth.…”

Long-term effect of Rayleigh–Taylor stabilization on converging Richtmyer–Meshkov instability

“…The converging RM instability has rarely been studied in a shock tube circumstance mainly due to the difficulty of generating a stable converging shock in laboratory conditions. There are only few works on the cylindrically converging shock (Perry & Kantrowitz 1951;Takayama, Kleine & Grönig 1987;Dimotakis & Samtaney 2006;Zhai et al 2010;Luo et al 2015) and, consequently, shock tube experiments on the converging RM instability are scarce (Hosseini & Takayama 2005;Si, Zhai & Luo 2014;Biamino et al 2015;Si et al 2015). Recently, two quantitative shock tube experiments were, respectively, reported in a semi-annular converging shock tube (Ding et al 2017) and a coaxial converging shock tube (Lei et al 2017), in which a reduction of growth rate was found and was ascribed to the RT stabilization effect caused by the interface deceleration motion existing in the converging circumstance.…”

Review of experimental Richtmyer–Meshkov instability in shock tube: From simple to complex

“…However, due to the limited apex angle of the converging geometry, the wedge boundaries often have significant influence on the evolution of the interface deformation and the shock propagation. To overcome these shortcomings, a semi-annular shock tube that combines the advantageous features of the above-mentioned two types of facilities was realized by Luo et al 123 The design of this shock tube followed the similar principle of an annular configuration, but the annular channel and the test section were cut into half and assembled in a self-strutted manner. In this way, the semi-annular configuration brings great convenience for interface formation and flow visualization, which are considered to be the two crucial ingredients in RM instability experiments.…”