认识稀薄气体动力学  

GET ACQUAINTED WITH RAREFIED GAS DYNAMICS

作　　者：沈青[1] 

机构地区：[1]中国科学院力学研究所,北京100080

出　　处：《力学与实践》2002年第6期1-14,共14页Mechanics in Engineering

基　　金：国家自然科学基金项目(19889209)资助.

摘　　要：以通俗易懂的方式介绍了空气动力学当气体间断分子效应显著时发展起来的特殊分支——稀薄气体动力学.讨论了非平衡现象与稀薄气体动力学的关系.通过与8速度气体模型的间断Boltzmann方程的对比,解释了Boltzmann方程碰撞项的物理意义和数学困难,简要综述了其一般解法.讨论了分子在物体表面的反射和问题的边界条件,着重介绍了直接模拟Monte Carlo(DSMC)方法和为克服低速稀薄流动(如MEMS中流动)中模拟困难的信息保存(IP)方法.This article introduces in an easy and understandable manner a specific branch of gas dynamics - rarefied gas dynamics, where discrete molecule effects prevail. The relationship between the non-equilibrium phenomena and rarefied gas dynamics is discussed. Through a comparison with the discrete Boltzmann equation for a 8-velocity gas model the collision term of the Boltzmann equation, its physical meaning and mathematical difficulties are elucidated and a brief review of the solution methods is also given. The reflexion of molecules from body surfaces and the slip boundary conditions are interpreted. The direct simulation Monte Carlo (DSMC) method and the information preservation (IP) method used to overcome the difficulties in simulating slow rarefied gas flows (such as in MEMS) are introduced and recommended.

关 键 词：稀薄气体动力学 BOLTZMANN方程 低速稀薄流动 IP方法 空气动力学 气体间断分子效应 

分 类 号：V211.25[航空宇航科学与技术—航空宇航推进理论与工程]