论文标题
通过具有速度依赖性碰撞频率的动力学模型来捕获稀有气流中分子间电位的影响
Capturing the influence of intermolecular potential in rarefied gas flows by a kinetic model with velocity-dependent collision frequency
论文作者
论文摘要
提出了一种称为$ν$模型的动力学模型，以替换复杂的玻尔兹曼碰撞操作员，以模拟稀有气体气体的稀有流。该模型遵循松弛时间近似，但是碰撞频率（即逆松弛时间）是分子速度的函数，反映了Boltzmann方程的碰撞细节的一部分，而目标速度分布函数（VDF）与Shakhov模型中使用的VDF宽松接近。基于强大非平衡性冲击波的数值模拟，半理论和半经验碰撞频率是针对不同分子间电位设计的：$ν$模型显示出明显提高的精度，并分析了基本机制。 $ν$ - 模型在规范稀有微流中表现良好，尤其是在热蒸腾过程中，在热蒸腾过程中，具有速度独立的碰撞频率的常规动力学模型缺乏区分分子间电位影响的能力。
A kinetic model called the $ν$-model is proposed to replace the complicated Boltzmann collision operator in the simulation of rarefied flows of monatomic gas. The model follows the relaxation-time approximation, but the collision frequency (i.e, inverse relaxation time) is a function of the molecular velocity to reflect part of the collision details of the Boltzmann equation, and the target velocity distribution function (VDF) to which the VDF relaxes is close to that used in the Shakhov model. Based on the numerical simulation of strong non-equilibrium shock waves, a half-theoretical and half-empirical collision frequency is designed for different intermolecular potentials: the $ν$-model shows significantly improved accuracy, and the underlying mechanism is analysed. The $ν$-model also performs well in canonical rarefied micro-flows, especially in the thermal transpiration, where the conventional kinetic models with velocity-independent collision frequency lack the capability to distinguish the influence of intermolecular potentials.
