The Richtmyer–Meshkov instability of a ‘V’ shaped air/ interface

Abstract

The Richtmyer–Meshkov instability on a ‘V’ shaped air/SF$_{6}$ gaseous interface is experimentally studied in a shock tube. By the soap film technique, a discontinuous interface without supporting mesh is formed so that the initial conditions of the interface can be accurately controlled. Five ‘V’ shaped air/$\text{SF}_{6}$ interfaces with different vertex angles ($60^{\circ }$, $90^{\circ }$, $120^{\circ }$, $140^{\circ }$ and $160^{\circ }$) are created where the ratio of the initial interface amplitude to the wavelength varies to highlight the effects of initial condition on the flow characteristics. The wave patterns and interface morphologies are clearly identified in the high-speed schlieren sequences, which show that the interface deforms in a less pronounced manner with less vortices generated as the vertex angle increases. A regime change is observed in the interface width growth rate near a vertex angle of $160^{\circ }$, which provides an experimental evidence for the numerical results obtained by McFarland et al. (Phys. Scr. vol. T155, 2013, 014014). The growth rate of interface width in the linear phase is compared with the theoretical predictions from the classical impulsive model and a modified linear model, and the latter is proven to be effective for a moderate to large initial amplitude. It is found that the initial growth rate of the interface width is a non-monotone function of the initial vertex angle (amplitude–wavelength ratio), i.e. the interface width growth rate in the linear stage experiences an increase and then a decrease as the vertex angle increases. A similar conclusion was also reached by Dell et al. (Phys. Plasmas, vol. 22, 2015, 092711) numerically for a sinusoidal interface. Finally, the general behaviour of the interface width growth in the nonlinear stage can be well captured by the nonlinear model proposed by Dimonte & Ramaprabhu (Phys. Fluids, vol. 22, 2010, 014104).

Evolution of shock-accelerated heavy gas layer

“…The suppression effect of the TS 1 on the second interface is considered by replacing a 02 with the average of a + 2 and a 02 according to the modified impulsive theory (Meyer & Blewett 1972). The secondary compression effect on the evolution of the interface with high initial amplitude is considered by introducing a reduction factor (ψ) to modify the initial amplitude growth rate (Buttler et al 2012;Luo et al 2016;Liang et al 2019). Then the modified MIK model (mMIK model) considering the compression effect can be written as…”

Convergent Richtmyer–Meshkov instability on two-dimensional dual-mode interfaces

“…The soap-film technique (Luo et al 2016;Liang et al 2021a;Guo et al 2022) is used to form the well-defined dual-mode interfaces. Before interface formation, the transparent devices (devices A and B) shown in figure 1(b) are manufactured by combining two transparent acrylic plates (3.0 mm in thickness) with pedestals (7.0 mm in height).…”

Advances in interfacial instability induced by reshock

“…激波诱导界面不稳定性, 又称为激波与界面相互 作用或Richtmyer-Meshkov (RM)不稳定性, 最早是由 Richtmyer [1] 在1960年做出理论预测, 并由Meshkov [2] [3] 、航天火箭发动机 [4] 、天体物理 [5] 等领域有着重要的研究和应用价值. 如, 它是惯性约束 [6][7][8][9][10][11][12][13][14][15][16][17][18][19] , 我国 学者也开展了丰富的研究工作并取得一系列重要进 展 [20][21][22][23][24][25][26][27][28][29] . 近年来, 相关的专题综述已经4次在Annual Review of Fluid Mechanics上发表 [30][31][32][33] .…”