Experimental study of Richtmyer-Meshkov instability in a cylindrical converging shock tube

Abstract

The interaction of a cylindrical converging shock wave with an initially perturbed gaseous interface is studied experimentally. The cylindrical converging shock is generated in an ordinary shock tube but with a specially designed test section, in which the incident planar shock wave is directly converted into a cylindrical one. Two kinds of typical initial interfaces involving gas bubble and gas cylinder are employed. A high-speed video camera combined with schlieren or planar Mie scattering photography is utilized to capture the evolution process of flow structures. The distribution of baroclinic vorticity on the interface induced by the cylindrical shock and the reflected shock from the center of convergence results in distinct phenomena. In the gas bubble case, the shock focusing and the jet formation are observed and the turbulent mixing of two fluids is promoted because of the gradually changed shock strength and complex shock structures in the converging part. In the gas cylinder case, a counter-rotating vortex pair is formed after the impact of the converging shock and its rotating direction may be changed when interacting with the reflected shock for a relatively long reflection distance. The variations of the interface displacements and structural dimensions with time are further measured. It is found that these quantities are different from those in the planar counterpart because of the shock curvature, the Mach number effect and the complex shock reflection within the converging shock tube test section. Therefore, the experiments reported here exhibit the great potential of this experimental method in study of the Richtmyer-Meshkov instability induced by converging shock waves.

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

“…In this work, the converging RM instability is quantitatively studied in a cylindrically converging shock tube which has already verified its feasibility and reliability for the studies of the converging RM instability in our previous work (Luo et al 2014a;Si et al 2014) and, therefore, only a brief description of this facility is given here. This shock tube consists of a 1.7 m driver section, a 2.0 m driven section and a 1.2 m test section.…”

“…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.…”

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

“…Based on shock dynamics theory, a convergent shock tube with a special wall profile which can smoothly convert a planar incident shock into a perfect cylindrical one was designed and manufactured (Zhai et al 2010). Subsequently, evolutions of various distorted interfaces accelerated by a cylindrical shock were examined in this facility (Si, Zhai & Luo 2014;Luo et al 2018). The convergent RMI at a single-mode heavy/light interface was realized by a gas lens technique which was originally proposed by Dimotakis & Samtaney (2006) and later extended by Vandenboomgaerde & Aymard (2011), and the experimental results exhibited great potential for studying the convergent RMI (Biamino et al 2015).…”

Progress in experiments of converging Richtmyer-Meshkov instability

“…Si等人 [38] 在该激波管中利用肥皂膜技术生成了 SF 6 气泡, 并成功开展了汇聚激波冲击SF 6 气泡的实 验研究, 利用高速纹影方法捕捉到了柱形激波-气泡 图 5 柱形激波冲击SF 6 /air单模界面 [37] Figure 5 Interaction of a cylindrical shock with a single-mode SF 6 /air interface [37] 相互作用的详细过程, 如图6所示. 实验结果表明, 受 Figure 6 Interaction of a cylindrical shock with a SF 6 bubble [38] 图 7 柱形激波与SF 6 气柱相互作用 [39] Figure 7 A cylindrical shock interacting with a SF 6 cylinder [39] 的相互诱导主导着后期界面的演化. Si等人 [39] Zou等人 [44,45] 开展了平面激波冲击椭圆形气柱以及扰 动激波与无扰动界面相互作用的实验研究, 获得了 许多可靠的实验数据.…”