云的湍流破坏-我。二维绝热激波-云相互作用模式中turbulence的k-ε处理
The turbulent destruction of clouds - I. A k-epsilon treatment of turbulence in 2D models of adiabatic shock-cloud interactions
摘要：
激波与云的相互作用已在文献中得到广泛研究，其中考虑了磁场、辐射冷却和热传导的影响。然而，充分发展的湍流的形成往往被阻止的人工粘性固有的流体动力学模拟，和一个统一的后冲击流已被假定在所有以前的单云研究。实际上，激波后面的流动也可能是湍流，当激波扫过云上游的不均匀性时，会产生不均匀的密度、压力和速度结构。为了解决这两个问题，我们使用一个亚网格可压缩k-ε湍流模型来估计激波云相互作用中产生的湍流的性质，以及由此产生的湍流带来的输运系数的增加。一个详细的比较，从一个无粘流体动力学代码的输出，把这些新的结果到上下文。我们发现，云破坏无粘和k-mills模型中发生在大致相同的速度时，激波后的流动是光滑的，当云和云间介质的密度差小于100。然而，随着这种对比度的增加，存在越来越大的显著差异。云受到强烈的“冲击”后高度动荡的环境的强烈“冲击”，破坏得更快。用无粘性代码进行的附加计算，其中激波后的流动是随机的，网格尺度的运动，证实了云的更快的破坏。我们的研究结果清楚地表明，湍流起着重要的作用，在激波云相互作用，环境湍流增加了一个新的维度的参数空间，迄今已研究（删节）。
英文摘要：
The interaction of a shock with a cloud has been extensively studied in the literature, where the effects of magnetic fields, radiative cooling and thermal conduction have been considered. However, the formation of fully developed turbulence has often been prevented by the artificial viscosity inherent in hydrodynamical simulations, and a uniform post-shock flow has been assumed in all previous single-cloud studies. In reality, the flow behind the shock is also likely to be turbulent, with non-uniform density, pressure and velocity structure created as the shock sweeps over inhomogenities upstream of the cloud. To address these twin issues we use a sub-grid compressible k-epsilon turbulence model to estimate the properties of the turbulence generated in shock-cloud interactions and the resulting increase in the transport coefficients that the turbulence brings. A detailed comparison with the output from an inviscid hydrodynamical code puts these new results into context. We find that cloud destruction in inviscid and k-epsilon models occurs at roughly the same speed when the post-shock flow is smooth and when the density contrast between the cloud and inter-cloud medium is less than 100. However, there are increasing and significant differences as this contrast increases. Clouds subjected to strong ``buffeting'' by a highly turbulent post-shock environment are destroyed significantly quicker. Additional calculations with an inviscid code where the post-shock flow is given random, grid-scale, motions confirms the more rapid destruction of the cloud. Our results clearly show that turbulence plays an important role in shock-cloud interactions, and that environmental turbulence adds a new dimension to the parameter space which has hitherto been studied (abridged).
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
