论文标题
在分子云集合的背景下,自我散热的等温湍流的密度分布函数-III。病毒分析
Density distribution function of a self-gravitating isothermal turbulent fluid in the context of molecular clouds ensembles -- III. Virial analysis
论文作者
论文摘要
在目前的工作中,我们将病毒分析应用于Donkov \&Stefanov引入的前两篇论文中引入的自我磨碎的湍流云集合模型,阐明了湍流的某些方面,并将模型扩展到不仅用于超音速流,还考虑到超音速流,还为反式和亚音言。我们以任意量表(远离云核)的方式使用Eulerian病毒定理,我们得出了密度曲线的方程式,并以近似方式求解它。结果证实了解决方案$ \ varrho(\ ell)= \ ell^{ - 2} $在上一篇论文中找到的。该解决方案对应于能量平衡的三种可能的配置。对于反式或亚音速流,我们在引力和热能之间或在重力,湍流和热能之间获得平衡(情况2),而对于超音速流,可能的平衡是在重力和湍流能量之间(情况3)。在情况1和2中,流体元件的能量可以为负或零端,因此溶液在动态稳定并应长期存在。在情况3中,流体元件的能量为正或零,即溶液不稳定或最多略有结合。在核心附近的尺度上,人们不能忽略气体惯性矩的第二个导数,从而防止了密度谱的分析方程的推导。但是,由于流体元件的能量消失,我们获得了核心附近的气体未被病毒,并且其状态略有结合。
In the present work we apply virial analysis to the model of self-gravitating turbulent cloud ensembles introduced by Donkov \& Stefanov in two previous papers, clarifying some aspects of turbulence and extending the model to account not only for supersonic flows but for trans- and subsonic ones as well. Make use of the Eulerian virial theorem at an arbitrary scale, far from the cloud core, we derive an equation for the density profile and solve it in approximate way. The result confirms the solution $\varrho(\ell)=\ell^{-2}$ found in the previous papers. This solution corresponds to three possible configurations for the energy balance. For trans- or subsonic flows, we obtain a balance between the gravitational and thermal energy (Case 1) or between the gravitational, turbulent and thermal energies (Case 2) while for supersonic flows, the possible balance is between the gravitational and turbulent energy (Case 3). In Cases 1 and 2 the energy of the fluid element can be negative or zero end thus the solution is dynamically stable and shall be long lived. In Case 3 the energy of the fluid element is positive or zero, i.e., the solution is unstable or at best marginally bound. At scales near the core, one cannot neglect the second derivative of the moment of inertia of the gas, which prevents derivation of an analytic equation for the density profile. However, we obtain that gas near the core is not virialized and its state is marginally bound since the energy of the fluid element vanishes.