统一气体动理学方法研究进展

在临近空间高超声速飞行器气动载荷、航天飞行器变轨/调姿、微尺度元器件传质/传热等科学和工程实践中,存在着大量的时序多流域(多尺度)流动问题以及位于单一流场中的复杂多流域问题(局部稀薄问题),对数值预测工作提出挑战.因此,近年来从介观气体动理学基础上发展出了一大类将连续流与稀薄流进行统一计算的高效数值方法,包括确定论形式的UGKS,GKUA和DUGKS方法,以及粒子形式的USP-BGK和UGKWP方法.文章围绕着确定论和统计粒子两类统一方法的最新研究进展进行回顾和分析,重点关注在每种方法中全流域统一性质的来源与实现方式、目前已取得的关键进展以及该方法的扩展性和应用价值.

Advance in Unified Methods Based on Gas-Kinetic Theory

In the scientific and engineering practices, such as the aerodynamic loads on near space aircrafts, the orbital transfer and attitude adjustment of spacecrafts, and the mass/heat transfer of micro-scale devices, there are a large amount of multi-regime (multi-scale) flows. The appearance of multi-regimes can be both sequential and spatial, and the latter one is recognized as the complicated local rarefied problem. Since the problem of multi-regime flows is a challenge to the numerical methods, a series of efficient methods which were designed to solve both the continuum flow and rarefied flow in a unified way were proposed in these years, such as the deterministic UGKS, GKUA and DUGKS methods, along with the USP-BGK and UGKWP methods in stochastic particle frameworks. In this paper, the deterministic unified methods and the stochastic unified methods were reviewed and discussed. For each method, the realization of its unified property was discussed along with the theoretical basis. The current advances, potential application value, and extendibility of each method were also discussed in this paper.