气体动理学格式及其在再入问题中的应用

Gas-kinetic scheme and its applications in re-entry flows

介绍了气体动理学格式GKS在飞行器高超声速再入过程涉及的跨流域稀薄及湍流等复杂流动问题中的拓展和应用。GKS利用BGK方程的通解来计算单元界面上的通量,耦合了分子的自由运动和相互碰撞,内涵多尺度特性。本文发展了耦合多种湍流模式的拓展GKS,能对典型高超声速湍流进行有效模拟。基于通量重构CPR框架发展了非结构网格上的高精度格式CPR-GKS,在可压缩黏性流动中可以同时保持高精度和良好的激波捕捉能力。为模拟航天器再入过程中的跨流域稀薄流动,发展了适合大规模并行计算的高效UGKS,并在再入问题中得到了很好的应用。研究揭示了GKS在再入问题模拟中的优异性能及其广阔的应用前景。

The gas-kinetic scheme(GKS)is expanded and applied in modeling the supersonic flow past re-entry vehicles with complex flow phenomena such as rarefied effect and turbulence.The GKS utilizes the general solution of the BGK equation to obtain the time evolving flux at the cell interface,coupling particle free transport and collisions,thus with inherent multiscale characteristics.In this work,based on the expanded BGK equation typical turbulence models are included in the GKS to effectively simulate typical supersonic turbulence with high Reynolds number.Based on the CPR,a high-order GKS on unstructured grid is developed for compressible viscous flows with capability to accurately capture shocks.To simulate the rarefied re-entry flow,high performance parallel algorithm for the UGKS is developed.These studys show the good performance of the GKS in re-entry flows and its good prospect for wide applications.