An experimental investigation of the turbulent mixing transition in the Richtmyer–Meshkov instability
An experimental investigation of the turbulent mixing transition in the Richtmyer–Meshkov instability
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DOI：
10.1017/jfm.2014.188
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发表时间：
2013-08
影响因子：
3.7
通讯作者：
C. Weber;N. Haehn;J. Oakley;D. Rothamer;R. Bonazza
中科院分区：
文献类型：
--
作者：
C. Weber;N. Haehn;J. Oakley;D. Rothamer;R. Bonazza
摘要在垂直激波管中，利用氦-丙酮混合物和氩（$A\approximat0.7 $）之间的界面上施加的宽带初始条件，对Richtmyer-Meshkov不稳定性（RMI）进行了实验研究。该接口是创建没有使用的膜，首先建立一个平坦的，重力稳定的停滞平面，在那里的气体被注入从端部的激波管和出口通过水平槽在接口位置。在此之后，通过在界面的平面内注入气体来扰动界面。由于该注入流与周围气体之间的剪切，在该层的下部形成扰动。这个剪切层作为一个统计上可重复的宽带初始条件的RMI。的接口是由$M= 1.6 $或$M= 2.2 $平面冲击波加速，并随后的混合层的发展进行了研究，使用平面激光诱导荧光（PLIF）。通过对PLIF图像进行处理，以通过考虑激光吸收和激光转向效应来揭示轻气体摩尔分数。这些图像表明，在实验过程中发生了向湍流混合的过渡。摩尔分数分布的分析证实了这种转变，表明气体开始均匀化在稍后的时间。标量方差能谱显示出接近$k^{-5/3}$的惯性范围，为湍流混合提供了进一步的证据。Batchelor和Taylor微尺度的测量是由摩尔分数图像，给出${\sim }150\ \mu \mathrm{m}$和4 mm，分别由最新的时间。这些尺度的比值意味着外尺度雷诺数为6\text {--}7\times 10^4$。
Abstract The Richtmyer–Meshkov instability (RMI) is experimentally investigated in a vertical shock tube using a broadband initial condition imposed on an interface between a helium–acetone mixture and argon ( $A\approx 0.7$ ). The interface is created without the use of a membrane by first setting up a flat, gravitationally stable stagnation plane, where the gases are injected from the ends of the shock tube and exit through horizontal slots at the interface location. Following this, the interface is perturbed by injecting gas within the plane of the interface. Perturbations form in the lower portion of this layer due to the shear between this injected stream and the surrounding gas. This shear layer serves as a statistically repeatable broadband initial condition to the RMI. The interface is accelerated by either a $M= 1.6 $ or $M= 2.2 $ planar shock wave, and the development of the ensuing mixing layer is investigated using planar laser-induced fluorescence (PLIF). The PLIF images are processed to reveal the light-gas mole fraction by accounting for laser absorption and laser-steering effects. The images suggest a transition to turbulent mixing occurring during the experiment. An analysis of the mole-fraction distribution confirms this transition, showing the gases begin to homogenize at later times. The scalar variance energy spectra exhibits a near $k^{-5/3}$ inertial range, providing further evidence for turbulent mixing. Measurements of the Batchelor and Taylor microscales are made from the mole-fraction images, giving ${\sim }150\ \mu \mathrm{m}$ and 4 mm, respectively, by the latest times. The ratio of these scales implies an outer-scale Reynolds number of $6\text {--}7\times 10^4$ .