Abstract

Explaining the causes of angular momentum transfer in accretion stellar disks is an important astrophysical problem, since it is the process that determines the rate of accretion of matter onto the central gravitating body. Previously, within the framework of a two-dimensional approach, it was shown that the introduction of small perturbations into the flow of accretion disk leads to the appearance of shear instability. This process is accompanied by the development of large-scale vortex structures. Their movement and evolution lead to a redistribution of angular momentum in the accretion disk. The action of the described mechanism was previously studied numerically only within a two-dimensional approximation, so the goal of the current work is to carry out full-scale three-dimensional modeling. The processes under study are described within the framework of the system of equations of ideal gas dynamics. The article briefly describes the method for their numerical integration, which is based on a conservative finite-difference scheme and the solution of the Riemann problem. The initial data is a stationary toroidal gas state surrounded by a matter with low density and pressure. At the next step, small perturbations of one of the gas-dynamic variables are introduced. The modeling and analysis of the results of numerical calculations show the emergence of vortex structures in the shear flow of a three-dimensional accretion disk. Their movement is accompanied by a redistribution of matter and angular momentum in the volume of the disk, leading to accretion of matter onto the central body.

中文翻译：

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恒星加速盘中大尺度涡旋结构的形成与演化

摘要

解释吸积恒星盘中角动量转移的原因是一个重要的天体物理学问题，因为它是决定物质吸积到中心引力体上的速率的过程。此前，在二维方法的框架内，研究表明，在吸积盘流动中引入小扰动会导致剪切不稳定的出现。这一过程伴随着大规模涡旋结构的发展。它们的运动和演化导致吸积盘中角动量的重新分布。之前仅在二维近似内对所描述的机构的作用进行了数值研究，因此当前工作的目标是进行全尺寸三维建模。所研究的过程是在理想气体动力学方程组的框架内描述的。本文简要介绍了它们的数值积分方法，该方法基于保守的有限差分格式和黎曼问题的求解。初始数据是由低密度和压力物质包围的静止环形气体状态。下一步，引入其中一个气体动力学变量的小扰动。数值计算结果的建模和分析表明三维吸积盘剪切流中出现了涡结构。它们的运动伴随着圆盘体积中物质和角动量的重新分布，导致物质吸积到中心体上。