On the validity of the Boltzmann-BGK model through relaxation evaluation

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	On the validity of the Boltzmann-BGK model through relaxation evaluation
	Sun QH(孙泉华); Cai CP; Gao W(高巍)
刊名	Acta Mechanica Sinica
	2014-04
通讯作者邮箱	qsun@imech.ac.cn
卷号	30 期号:2 页码:133-143
关键词	BGK model Boltzmann equation Validity evaluation DSMC method Time relaxation
ISSN号	0567-7718
通讯作者	Sun, QH (reprint author), Chinese Acad Sci, Inst Mech, State Key Lab High Temp Gas Dynam, Beijing 100190, Peoples R China.
产权排序	[Sun, Quan-Hua; Gao, Wei] Chinese Acad Sci, Inst Mech, State Key Lab High Temp Gas Dynam, Beijing 100190, Peoples R China; [Cai, Chun-Pei] New Mexico State Univ, Dept Mech & Aerosp Engn, Las Cruces, NM 88001 USA
合作状况	国内
中文摘要	The Boltzmann-Bhatnagar-Gross-Krook (BGK) model is investigated for its validity regarding the collision term approximation through relaxation evaluation. The evaluation is based on theoretical analysis and numerical comparison between the BGK and direct simulation Monte Carlo (DSMC) results for three specifically designed relaxation problems. In these problems, one or half component of the velocity distribution is characterized by another Maxwellian distribution with a different temperature. It is analyzed that the relaxation time in the BGK model is unequal to the molecular mean collision time. Relaxation of component distribution fails to involve enough contribution from other component distributions, which makes the BGK model unable to capture details of velocity distribution, especially when discontinuity exists in distribution. The BGK model, however, predicts satisfactory results including fluxes during relaxation when the temperature difference is small. Particularly, the model-induced error in the BGK model increases with the temperature difference, thus the model is more reliable for low-speed rarefied flows than for hypersonic flows.
分类号	二类
收录类别	SCI ; EI ; CSCD
资助信息	The project was supported by the National Natural Science Foundation of China (91116013, 11372325, and 11111120080).
原文出处	http://dx.doi.org/10.1007/s10409-014-0017-x
语种	英语
WOS记录号	WOS:000334677600002
公开日期	2014-06-05
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/48847]
专题	力学研究所_高温气体动力学国家重点实验室
推荐引用方式 GB/T 7714	Sun QH,Cai CP,Gao W. On the validity of the Boltzmann-BGK model through relaxation evaluation[J]. Acta Mechanica Sinica,2014,30(2):133-143.
APA	Sun QH,Cai CP,&Gao W.(2014).On the validity of the Boltzmann-BGK model through relaxation evaluation.Acta Mechanica Sinica,30(2),133-143.
MLA	Sun QH,et al."On the validity of the Boltzmann-BGK model through relaxation evaluation".Acta Mechanica Sinica 30.2(2014):133-143.