空气动力学学报2013，Vol.31Issue(1)：1-8,8.DOI:10.7638/kqdlxxb20130101
DSMC方法中的统计噪声分析
Analysis of statistical noise in DSMC method
摘要
Abstract
On the basis of analysis of the simulation principles for the DSMC method based on particle transportation stochastic simulations, the statistical noise, relative statistical fluctuations and their confidences are defined.According to the Chebysheve inequality in probability theory, the theoretical formulas on statistical fluctuations of flow velocity and temperature in the flow field are deduced and presented by using equilibrium statistical theory of normal distribution.Then, their correctness and adaptability are numerically validated and theoretically analyzed by examples of the planar Couette shear flow in the transition flow regime and the normal shock wave flow.It is shown that, under certain confidences and the proper choice of simulating parameters, the statistical noise from the DSMC simulation is inversely proportional to the square root of the sample size (number of simulated molecules and statistical sampling times) , and the relative statistical fluctuation of the flow velocity is inversely proportional to local Mach number of the flow field, but the relative statistical fluctuation of the temperature is independent of macroscopic flow parameters besides.The studies provide theoretical guidelines and computational criteria for controlling the relative statistical fluctuations from the DSMC simulation.关键词
DSMC 方法/统计噪声/相对统计涨落/Couette流动/激波结构Key words
DSMC method/ statistical noise/ relative statistical fluctuation/ Couette flow/ shock-wave structures分类
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李志辉,方明,唐少强..DSMC方法中的统计噪声分析[J].空气动力学学报,2013,31(1):1-8,8.基金项目
国家自然科学基金(91016027),国防基础科研基金(51313030104) （91016027）
