Rates of thermal relaxation in direct simulation Monte Carlo methods
Rates of thermal relaxation in direct simulation Monte Carlo methods
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DOI：
10.1063/1.868221
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发表时间：
1994-06
影响因子：
4.6
通讯作者：
B. Haas;D. Hash;G. Bird;F. Lumpkin;H. Hassan
中科院分区：
文献类型：
--
作者：
B. Haas;D. Hash;G. Bird;F. Lumpkin;H. Hassan
对于稀薄气体混合物的内能弛豫，导出了直接模拟蒙特卡罗（DSMC）方法中的选择概率P与Jeans方程中由碰撞数Z决定的宏观弛豫速率之间的精确关系。这些表达式适用于内部能量交换力学的Borgnakke-Larsen模型，并且不限于常数Z的假设。虽然Jeans方程导致绝热弛豫曲线，合并到一个单一的解决方案时，绘制对碰撞的累积次数，它表明，Borgnakke-Larsen选择概率取决于分子间的潜力，内部自由度的数量，和DSMC选择方法。此外，模拟结果表明，通常的假设P=1/Z是无效的，在一般情况下，并导致相当慢的弛豫比规定的Z在Jeans的方程。此外，在文献中出现的碰撞率的不一致的定义可以…
For internal energy relaxation in rarefied gas mixtures, exact relationships are derived between the selection probability P employed in direct simulation Monte Carlo (DSMC) methods and the macroscopic relaxation rates dictated by collision number Z in Jeans’ equation. These expressions apply to the Borgnakke–Larsen model for internal energy exchange mechanics and are not limited to the assumption of constant Z. Although Jeans’ equation leads to adiabatic relaxation curves, which coalesce to a single solution when plotted against the cumulative number of collisions, it is shown that the Borgnakke–Larsen selection probabilities depend upon the intermolecular potential, the number of internal degrees of freedom, and the DSMC selection methodology. Furthermore, simulation results show that the common assumption P=1/Z is invalid, in general, and leads to considerably slower relaxation than stipulated by Z in Jeans’ equation. Moreover, inconsistent definitions of collision rates appearing in the literature can...