为了模拟跨流域复杂物形绕流或多体流场,需要在位置空间建立能描述整个流场特性的网格系统,相应的数值计算方法也需要有所改进。本文采用分区对接网格处理复杂物形绕流或多体干扰流场,得到能准确描述流场特征的贴体网格系统。在此基础上数值求解考虑转动非平衡影响的 Boltzmann-Rykov 模型方程,在速度空间应用离散速度坐标法、位置空间采用数值差分 NND 格式。网格对接面上考虑分布函数的传递,包含网格点信息和网格点上速度的信息。通过计算得到复杂物形的流动特性。相关算例表明网格分区之间的流场参数光滑过渡。与文献及 DSMC 结果的对比证实本文基于分区对接网格的气体运动论统一算法是可靠的。
In order to simulate gas flows with complex shapes or several bodies covering vari-ous regimes,coordinate space should be divided into dinky cells,and numerical method based on the complex mesh system should also be developed.In this paper,two-dimensional flows around complex objects are described by multi-block patched meshes,and then body-fitted mesh systems are given.Boltzmann-Rykov model equation involving rotational non-equilibrium effect is numeri-cally computed based on this mesh system.Discrete velocity ordinate method is used to disperse velocity space,while finite-difference NND scheme for coordinate space.Transfer of distribution function on the interface,information and velocity information on the grid included,should be treated especially.Then flow characters from rarefied transition to continuum around complex bodies are obtained by numerical computing.Some examples show that macro-parameters glossi-ly translate between different blocks in the whole mesh system.Results from GKUA are com-pared with those from reference and DSMC method.It is showed that the Gas-kinetic Unified Al-gorithm based on multi-block patched mesh is credible to numerically simulate complex flows in various regimes.