论文标题
粒子中间平面层的湍流形成磁盘
Turbulence in particle laden midplane layers of planet forming disks
论文作者
论文摘要
我们检查了形成磁盘的固定粒子层，其中流媒体不稳定性（SI）被认为是弱或不活跃的。在$ 0.2H $大小的盒子中，一套低至中等分辨率的三维模拟，其中$ h $是压力尺度的高度，使用铅笔进行两个stokes编号，\ st $ = 0.04 $和$ 0.2 $，以1 \％\％的磁盘金属性进行。我们发现，出现了一系列Ekman-layer喷气流的复杂性，受三个线性增长的过程的出现：（1）Kelvin-Helmholtz不稳定性（KHI），（2）（2），（2）行星形成的磁盘类似物类似于行星对称对称性不稳定性（SYMI），以及（3）以后无效的次数延伸，可能是一定的，可能是一定的，可能是一定的一部分。传播模式状态。对于\ st $ = 0.2 $，KHI是主导的，并且表现为中型轴对称卷，而对于\ st $ = 0.04 $，轴对称Symi主要驱动湍流。 Symi是在模型磁盘流中进行分析开发的，预测当粒子气中间平面层的richardson数（RI）以下1以下时，它表现出生长速率$ \ le \ le \ sqrt {2/\ ri -2} \cdotΩ$，其中$ω$是本地disk旋转率。对于相当普遍的情况，没有湍流的外部来源，可以猜想SI（如果启动时）出现在湍流状态中，主要由至少由Symi和/或KHI驱动和塑造。我们还发现，以$ 256^3 $分辨率模拟产生的湍流没有统计融合，并且相应的$ 512^3 $模拟可以以\ st $ = 0.2 $收敛。此外，我们报告说，我们的数值模拟在小于6-8个网格点上显着耗散湍流动能。
We examine the settled particle layers of planet forming disks in which the streaming instability (SI) is thought to be either weak or inactive. A suite of low-to-moderate resolution three-dimensional simulations in a $0.2H$ sized box, where $H$ is the pressure scale height, are performed using PENCIL for two Stokes numbers, \St$=0.04$ and $0.2$, at 1\% disk metallicity. We find a complex of Ekman-layer jet-flows emerge subject to three co-acting linearly growing processes: (1) the Kelvin-Helmholtz instability (KHI), (2) the planet-forming disk analog of the baroclinic Symmetric Instability (SymI), and (3) a later-time weakly acting secondary transition process, possibly a manifestation of the SI, producing a radially propagating pattern state. For \St$=0.2$, KHI is dominant and manifests as off-midplane axisymmetric rolls, while for \St$=0.04$ the axisymmetric SymI mainly drives turbulence. SymI is analytically developed in a model disk flow, predicting that it becomes strongly active when the Richardson number (Ri) of the particle-gas midplane layer transitions below 1, exhibiting growth rates $\le\sqrt{2/\Ri - 2}\cdotΩ$, where $Ω$ is local disk rotation rate. For fairly general situations absent external sources of turbulence it is conjectured that the SI, when and if initiated, emerges out of a turbulent state primarily driven and shaped by at least SymI and/or KHI. We also find that turbulence produced in $256^3$ resolution simulations are not statistically converged and that corresponding $512^3$ simulations may be converged for \St$=0.2$. Furthermore, we report that our numerical simulations significantly dissipate turbulent kinetic energy on scales less than 6-8 grid points.
