论文标题
冷却驱动的凝结
Cooling driven coagulation
论文作者
论文摘要
天体物理气体，例如星际，围层或簇内中间的气体通常是多相，它提出了这些系统结构的问题。尽管有许多已知的过程导致嵌入（湍流）热介质中的冷气体化，但在这项工作中，我们专注于反向过程：凝结。这通常在风孔和剪切层模拟中可以看到，那里冷气碎片自发地结合。使用2D和3D流体动力学模拟，我们发现足够大（$ \ gg c _ {\ rm s} t _ {\ rm -cool} $），扰动的冷气云会产生脉动，可确保冷气质量增长，从而在长时间的时间内（$ \ gg r / c _ c _ {$ \ gg r / c _ {\ rm s} $）。这种质量生长有效地加速了热气体，这又会夹带冷液滴，从而导致凝血。冷气液滴之间有吸引力的反平方力具有与重力相似的有趣相似之处。 “单子”是表面积而不是质量。我们开发了一个简单的分析模型，该模型再现了我们的数值发现。
Astrophysical gases such as the interstellar-, circumgalactic- or intracluster-medium are commonly multiphase, which poses the question of the structure of these systems. While there are many known processes leading to fragmentation of cold gas embedded in a (turbulent) hot medium, in this work, we focus on the reverse process: coagulation. This is often seen in wind-tunnel and shearing layer simulations, where cold gas fragments spontaneously coalesce. Using 2D and 3D hydrodynamical simulations, we find that sufficiently large ($\gg c_{\rm s} t_{\rm cool}$), perturbed cold gas clouds develop pulsations which ensure cold gas mass growth over an extended period of time ($\gg r / c_{\rm s}$). This mass growth efficiently accelerates hot gas which in turn can entrain cold droplets, leading to coagulation. The attractive inverse square force between cold gas droplets has interesting parallels with gravity; the `monopole' is surface area rather than mass. We develop a simple analytic model which reproduces our numerical findings.
