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题名	恒星湍对流过程研究以及在盾牌座Delta型变星中的验证
作者	许华崟
学位类别	博士
答辩日期	2007-03-30
授予单位	中国科学院研究生院（云南天文台）
授予地点	北京
导师	李焱
关键词	恒星结构和演化 湍流 对流理论 对流超射 恒星振动
其他题名	The turbulence processes of stellar convection and its effects on the oscillation of a Delta Scuti star
学位专业	天体物理
中文摘要	恒星对流对结构和演化影响很大，一直以来都是用混合长理论来描述，后来发展的二阶多方程非局地理论比混合长理论更合理，但在数值计算方面存在困难。二阶可调参数模型在湍流模型中具有很宽的适用范围，本文的工作主旨就是通过对可调参数模型的研究，逐步建立一个通用二阶对流模型。 引言中介绍湍流研究历史，方法和现状，和湍流模式理论，阐述我们对湍流现象的基本观点，比较地球实验和太阳对流观测，演示二阶湍对流理论的推导过程。第二章简要介绍本文所采用的半经验可调参数模型，详细分析数值方法。 第三章在1Ms恒星模型中比较非局地对流理论和局地理论的区别，说明本文采用的模型兼顾可算性和合理性，分析湍流过程认识湍流压的简化方法。第四章对盾牌座Delta型变星FG Vir进行多组1.85Ms恒星模型计算和振动分析。模型表明非局地和局地两类对流理论在恒星结构上是相似的，但外部对流区的湍流量却相差巨大；绝热和非绝热振动分析表明两者具有不同的稳定性；最后合理地验证了该星频率。总之，该模型不仅合理描述1Ms恒星的外部单层厚对流，还构造出1.85Ms恒星的双层薄不稳定区的对流运动特征和振动特征，显示二阶模型比混合长更合理，适用更广。
英文摘要	Turbulence is ubiquitous in astrophysics, ranging from cosmology, interstellar medium to stars, accretion disks, etc. Stars exist rely on turbulence convection to transport heat when radiate process is insufficient. But common usage of phenomenological turbulence expressions in stellar convection, just like mixing-length theory makes turbulent convection models perennially unpredictive. At the same time, Reynolds stress models (RSM) are deduced by many researchers, but it is hard to apply them in the stellar structure and evolution, mainly because the calculation of the differential turbulence convection equations is the main obstacle on the way to the better theories. Our study is focused on the semi-empirical theory, especially in different turbulence processes. We apply the theory into two kinds of stars during their Main Sequence, which are 1Msun star and 1.85Msun star. In Chapter I, the importance of turbulence is recalled with the development process. The historical and characters of turbulence are introduced. Then we showed our understanding to turbulence in one section since the turbulence is an unknown and controversial question up to now. In Chapter II, the numerical method of turbulent convection theory is carefully constructed. We analyzed the convection stability in the turbulence modeling and finally constructed an effective numerical method to solve the equations. In Chapter III and Chapter IV, we focus on how much our convection theory can describe turbulence in two kinds of stars. We firstly deduced the medial and local theory from the non-local formula, and then mainly compared the non-local with the local theories. In solar-like star, all the description of turbulence in the models, namely diffusion, dissipation, isotropic and buoyancy, were agreed well with the characters of turbulence. In the delta Scuti type stars, the present conclusion were reconfirmed and we found the turbulent value in the non-local models are greatly lager than those in the local models. Furthermore, we made models of one of the delta Scuti type stars, named FG Vir. Generally speaking, all of this work showed the semi-empirical convection theory is better than the mixing-length theory.
语种	中文
学科主题	天文学
页码	122
内容类型	学位论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/5322]
专题	云南天文台_恒星物理研究组
推荐引用方式 GB/T 7714	许华崟. 恒星湍对流过程研究以及在盾牌座Delta型变星中的验证[D]. 北京. 中国科学院研究生院（云南天文台）. 2007.

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