Interstellar clouds in high-speed, supersonic flows: Two-dimensional simulations
Interstellar clouds in high-speed, supersonic flows: Two-dimensional simulations
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DOI：
10.1086/175167
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发表时间：
1995-01
期刊：
影响因子：
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通讯作者：
A. Schiano;W. Christiansen;J. Knerr
中科院分区：
文献类型：
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作者：
A. Schiano;W. Christiansen;J. Knerr
我们提出了一系列气体动力学模拟的密集，冷却星际云与高速，超音速风限制和加速嵌入的云的相互作用。我们的目标是试图确定这些云是否能够经受住各种潜在的破坏性不稳定，这些不稳定发生在它们的外围，足够长的时间加速到与风速相当的速度。这些模拟都是在轴对称(关于云轴)和‘板条’几何网格上使用二维欧拉气体动力学进行的。模拟的空间和时间分辨率在很大范围内变化，以调查小尺度不稳定对云的整体加速和大范围、破坏性不稳定发展的影响。通过改变风速常数约12公里/S(相当于10000 K的云温度)，研究了风云马赫数变化的影响。目前的模拟跟踪云的演变，因为它们被加速到大约比内部声速高4-5倍的速度。此外，对于最大尺度不稳定性，具有最高分辨率的模式被扩展到远远超过准线性Rayleigh-Taylor增长时间，达到最大尺度不稳定的6-7 Rayleigh-Taylor增长时间，然后由于后方网格边界的误差累积而被终止。
We present a series of gasdynamical simulations of the interaction of a dense, cool interstellar cloud with a high-speed, supersonic wind that confines and accelerates the embedded cloud. Our goal is to attempt to determine if such clouds can survive various potentially disruptive instabilities, that occur at their peripheries, long enough to be accelerated to speeds which are comparable to the wind velocity. These simulations are performed using two-dimensional, Eulerian gas dynamics on both an axisymmetric (about the cloud axis) and 'slab' geometric grid. The spatial and temporal resolutions of the simulations are varied over a wide range to investigate the effects of small-scale instabilities on the overall acceleration of clouds and the development of large-scale, disruptive instabilities. Also, we study the effects of wind/cloud Mach number variations by changing the wind speed constant at about 12 km/s (which corresponds to a cloud temperature of 10,000 K). The current simulations track the evolution of clouds as they are accelerated to speeds approximately 4-5 times greater than their internal sound speeds. Furthermore, the models with the highest resolution were extended far beyond quasi-linear Rayleigh-Taylor growth times reaching 6-7 Rayleigh-Taylor growth times for the largest scale instabilities before being terminated because of the accumulation of errors at the rear grid boundary.