Analogues of Rayleigh-Taylor and Richtmyer-Meshkov instabilities in flows with nonuniform particle and droplet seeding
Analogues of Rayleigh-Taylor and Richtmyer-Meshkov instabilities in flows with nonuniform particle and droplet seeding
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具有不均匀粒子和液滴播种的流动中的 Rayleigh-Taylor 和 Richtmyer-Meshkov 不稳定性的类似物
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发表时间：
2011
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通讯作者：
Sanjay Kumar
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作者：
P. Vorobieff;M. Anderson;J. Conroy;R. White;C. Truman;Sanjay Kumar
众所周知的Rayleigh-Taylor（RT）和Richtmyer-Meshkov（RM）不稳定性表征了两种不同密度的气体（或流体）由于重力（RT）或由于脉冲加速度（RM）而混合的流动行为。最近，在两相流中已经观察到类似的不稳定性，其中第二相的引晶密度，例如，气体中的颗粒或液滴以及所得到的平均密度最初是不均匀的。所述强制使第二相相对于包埋介质移动。在足够的接种浓度下，这导致包埋相的夹带。由此产生的运动类似于在没有第二相种子的混合流中演化的运动，但是密度不均匀（不像较轻和较重气体的混合），其中RT和RM不稳定性分别在重力诱导和脉冲加速度的情况下发展。水文程序SHAMRC在过去被用来研究RM不稳定性的形成和发展。在这里，我们试图用它来模拟一阶的形成和增长现象的新的一类不稳定的两相流第一，通过近似的第二相作为一个连续的流体的平均密度，第二，通过考虑相对运动的颗粒（液滴）到accountexplanation。改变初始条件以提供宽范围的不稳定性增长率。数值计算结果与实验结果的比较表明，吻合良好。
The well-knownRayleigh-Taylor(RT) and Richtmyer-Meshkov(RM) instabilities characterize the behavior of flows where two gases (or fluids) of different densities mix due to gravity (RT) or due to impulsive acceleration (RM). Recently, analogous instabilities have been observed in two-phase flows where the seeding density of the second phase, e.g., particles or droplets in gas, and the resulting average density, is initially non-uniform. The forcing causes the second phase to move with respect to the embedding medium. With sufficient seeding concentration, this leads to entrainment of the embedding phase. The resulting movement is similar to the movement that would evolve in a mixing flow with no secondphaseseeding,butwithnon-uniformdensity(notunlikeamixtureoflighter and heavier gases), where RT and RM instabilities develop in the case of gravityinduced and impulsive acceleration, respectively. The hydrocode SHAMRC has been used in the past to study the formation and growth of the RM instability. Here we attempt to use it to model the first order formation and growth phenomena of the new class of instability in two-phase flows first, by approximating the second phase as a continuous fluid with an averaged density, and second, by taking the relative motion of particles (droplets)into accountexplicitly. The initial conditions are varied to provide a wide range of instability growth rates. Comparison of the numerical results with experiment shows good agreement.