Research on accretion discs by Direct Simulation Monte Carlo Method

吸积盘的直接模拟蒙特卡罗方法研究

基本信息

批准号：
13640241
负责人：
MATSUDA Takuya
金额：
$ 2.11万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

We have investigated gas flows in close binary systems. The targets of the present research are an accretion disc, a surface flow on a gas-loosing star, a wind accretion flow and a viscosity in a rotating gas. We studied these targets mainly by numerical techniques. The methods of calculation are both a Direct Simulation Monte Carlo Method (DSMC) and a finite volume method.In three-dimensional finite volume calculations of accretion discs, we confirmed the presence of spiral shocks, which we had discovered earlier. On the other hand, we found only traces of the spiral shocks in DSMC calculations. The reason is probably insufficient resolution at the peripheral region of the disc. In such a rarefied region, the number of particles may not be enough to guarantee occurrence of collisions between particles, which are the essential ingredient to ensure the fluidal nature of the collection of particles. This difficulty is yet to be solved.We made three-dimensional hydrodynamic simulations of flows on the surface of the mass-losing star. We discovered complex eddies produced by high/low pressure on the stellar surface. We composed Doppler maps to compare the present theoretical results with observations of super-soft X-ray sources, and we found a good agreement.Wind accretion is an important mechanism of mass exchange in close binary systems. We computed the mass accretion ratio, which is defined as a ratio of mass-accretion rate to mass-loss rate, and derived an experimental formula. We also computed specific angular momentum loss from the system by stellar wind. These parameters are important factors in order to investigate the evolution of binary systems.Transfer of angular momentum in an accretion disc is an important factor to investigate the physics of accretion discs. We pointed out that the derivation of the formula of angular momentum transfer appeared in two famous textbooks were not correct. We proposed a correct way to derive this formula.

我们研究了封闭二元系统中的气体流动。目前研究的目标是吸积盘、气体流失恒星上的表面流、风吸积流和旋转气体中的粘度。我们主要通过数值技术研究这些目标。计算方法有直接模拟蒙特卡罗法(DSMC)和有限体积法。在吸积盘的三维有限体积计算中，我们证实了我们之前发现的螺旋激波的存在。另一方面，我们在 DSMC 计算中只发现了螺旋激波的痕迹。原因可能是光盘外围区域的分辨率不够。在这样一个稀薄的区域，颗粒的数量可能不足以保证颗粒之间发生碰撞，而颗粒之间的碰撞是确保颗粒集合的流体性质的重要因素。这个难题还有待解决。我们对质量损失恒星表面的流动进行了三维流体动力学模拟。我们发现恒星表面的高/低压产生复杂的涡流。我们绘制了多普勒图，将目前的理论结果与超软X射线源的观测结果进行了比较，我们发现了很好的一致性。风吸积是紧密双星系统中质量交换的重要机制。我们计算了质量吸积比，其定义为质量吸积率与质量损失率之比，并推导出了一个实验公式。我们还计算了系统因恒星风而损失的特定角动量。这些参数是研究双星系统演化的重要因素。吸积盘中角动量的传递是研究吸积盘物理的重要因素。我们指出两本著名教科书中出现的角动量传递公式的推导是不正确的。我们提出了推导该公式的正确方法。

项目成果

期刊论文数量（18）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

D.V.Bisikalo: "A Model of Superoutbursts in Binaries of SU Uma Type"Astronomy Reports. (出版予定). (2004)

D.V.Bisikalo：“SU Uma 型双星中的超级爆发模型”天文学报告（即将出版）。

DOI：
发表时间：
期刊：
影响因子：
0
作者：
通讯作者：

A Paradox of Two Space Ships in Special Relativity

狭义相对论中两艘太空船的悖论

DOI：
发表时间：
2004
期刊：
AAPPS Bulletin 14.1
影响因子：
0
作者：
D.V.Bisikalo;A.A.Boyarchuk;P.V.Kaygorodov;O.A.Kuznetsov;T.Matsuda;松田卓也;松田卓也
通讯作者：
松田卓也

Comment on "On the interaction of the solar wind with the interstellar medium : Field aligned MHD flow" by R.Ratkiewicz and G.M.Webb

R.Ratkiewicz 和 G.M.Webb 对“太阳风与星际介质的相互作用：场对准 MHD 流”的评论

DOI：
发表时间：
2004
期刊：
Journal Geophys. Res. 109
影响因子：
0
作者：
N.Pogorelov;T.Matsuda
通讯作者：
T.Matsuda

Is angular momentum in an accretion disk transported inwards?

吸积盘中的角动量是否向内传输？

DOI：
发表时间：
2001
期刊：
Progress of Theoretical Physics 105
影响因子：
0
作者：
D.V.Bisikalo;A.A.Boyarchuk;P.V.Kaygorodov;O.A.Kuznetsov;T.Matsuda;松田卓也;松田卓也;D.V.Bisikalo;岡和孝;松田卓也;岡和孝;林英二
通讯作者：
林英二

Direct Monte Carlo simulation of accretion disc.

吸积盘的直接蒙特卡罗模拟。