Multiphase Gas and the Fractal Nature of Radiative Turbulent Mixing Layers
Multiphase Gas and the Fractal Nature of Radiative Turbulent Mixing Layers
复制标题
多相气体和辐射湍流混合层的分形性质
作者：
D. Fielding;E. Ostriker;G. Bryan;A. Jermyn
在星系和星系间气体中，一种常见的情况是相对于热扩散气体运动的冷致密气体。开尔文-亥姆霍兹不稳定性产生了一个紊流混合层，并占据了通常迅速冷却的中温阶段。冷却损失的能量通过热的高焓气体平流进入混合层来平衡，从而导致冷相的生长和加速。这一过程可能在确定星际介质和环星系介质相结构以及加速星系风和宇宙细丝中的冷气体方面发挥重要作用。这些混合层的冷却发生在一个薄的波纹板上，我们认为它的分形维数为D = 5/2，其厚度可以调整以匹配热相混合时间和冷却时间。这些冷却片的特性构成了一个新模型的基础，该模型描述了冷却速率和热气体流入速度如何取决于系统的尺寸L、混合相的冷却时间、相对速度和密度对比。在短、大和大的环境中，娱乐功能有望得到增强。通过大量的三维流体动力学模拟，我们证明了这种分形冷却层模型准确地捕捉了湍流界面的能量学和演化，因此可以作为理解具有强辐射冷却的多相混合的基础。
A common situation in galactic and intergalactic gas involves cold dense gas in motion relative to hot diffuse gas. Kelvin–Helmholtz instability creates a turbulent mixing layer and populates the intermediate-temperature phase, which often cools rapidly. The energy lost to cooling is balanced by the advection of hot high enthalpy gas into the mixing layer, resulting in growth and acceleration of the cold phase. This process may play a major role in determining the interstellar medium and circumgalactic medium phase structure, and accelerating cold gas in galactic winds and cosmic filaments. Cooling in these mixing layers occurs in a thin corrugated sheet, which we argue has an area with fractal dimension D = 5/2 and a thickness that adjusts to match the hot phase mixing time to the cooling time. These cooling sheet properties form the basis of a new model for how the cooling rate and hot gas inflow velocity depend on the size L, cooling time of the mixed phase , relative velocity , and density contrast of the system. Entrainment is expected to be enhanced in environments with short , large , and large . Using a large suite of three-dimensional hydrodynamic simulations, we demonstrate that this fractal cooling layer model accurately captures the energetics and evolution of turbulent interfaces and can therefore be used as a foundation for understanding multiphase mixing with strong radiative cooling.
DOI：
10.3847/1538-4357/ab378f
发表时间：
2018-11
期刊：
The Astrophysical Journal
影响因子：
--
作者：
C. Hummels;Britton D. Smith;P. Hopkins;B. O’Shea;Devin W. Silvia;J. Werk;N. Lehner;J. Wise;D. Collins;Iryna S. Butsky
通讯作者：
C. Hummels;Britton D. Smith;P. Hopkins;B. O’Shea;Devin W. Silvia;J. Werk;N. Lehner;J. Wise;D. Collins;Iryna S. Butsky
影响因子：
4.8
作者：
Zhihui Li;P. Hopkins;J. Squire;C. Hummels
通讯作者：
Zhihui Li;P. Hopkins;J. Squire;C. Hummels
低质量星系中的银河风
DOI：
10.3847/1538-4357/ab4c37
发表时间：
2019
期刊：
The Astrophysical Journal
影响因子：
--
作者：
McQuinn, Kristen. B.;van Zee, Liese;Skillman, Evan D.
通讯作者：
Skillman, Evan D.