Ablation flows around entry bodies are at highly nonequilibrium states. This paper pre- sents comprehensive computational fluid dynamics simulations of such hypersonic flow examples. The computational scheme adopted i...Ablation flows around entry bodies are at highly nonequilibrium states. This paper pre- sents comprehensive computational fluid dynamics simulations of such hypersonic flow examples. The computational scheme adopted in this study is based on the Navie-Stokes equations, and it is capable of simulating multiple-dimensional, non-equilibrium, chemically reacting gas flows with multiple species. Finite rate chemical reactions, multiple temperature relaxation processes, and ion- izations phenomena with electrons are modeled. Simulation results of several hypersonic gas flows over axisymmetric bodies are presented and compared with results in the literature. It confirms that some past treatment of adopting less species for hypersonic flows is acceptable, and the differences from more species and more chemical reactions are not significant.展开更多
This paper presents a gaskinetic study on high-speed, highly rarefied jets expanding into a vacuum from a cluster of planar or annular exits. Based on the corresponding exact expressions for a planar or annular jet, i...This paper presents a gaskinetic study on high-speed, highly rarefied jets expanding into a vacuum from a cluster of planar or annular exits. Based on the corresponding exact expressions for a planar or annular jet, it is convenient to derive the combined multiple jet flowfield solutions of density and velocity components. For the combined temperature and pressure solutions, extra attention is needed. Several direct simulation Monte Carlo simulation results are provided to validate these analytical solutions. The analytical and numerical solutions are essentially identical for these high Knudsen number jet flows.展开更多
文摘Ablation flows around entry bodies are at highly nonequilibrium states. This paper pre- sents comprehensive computational fluid dynamics simulations of such hypersonic flow examples. The computational scheme adopted in this study is based on the Navie-Stokes equations, and it is capable of simulating multiple-dimensional, non-equilibrium, chemically reacting gas flows with multiple species. Finite rate chemical reactions, multiple temperature relaxation processes, and ion- izations phenomena with electrons are modeled. Simulation results of several hypersonic gas flows over axisymmetric bodies are presented and compared with results in the literature. It confirms that some past treatment of adopting less species for hypersonic flows is acceptable, and the differences from more species and more chemical reactions are not significant.
基金NSF-DMS-0914706the Research Enhancement Awards from the New Mexico Space GrantsNSF-CBET-0854411
文摘This paper presents a gaskinetic study on high-speed, highly rarefied jets expanding into a vacuum from a cluster of planar or annular exits. Based on the corresponding exact expressions for a planar or annular jet, it is convenient to derive the combined multiple jet flowfield solutions of density and velocity components. For the combined temperature and pressure solutions, extra attention is needed. Several direct simulation Monte Carlo simulation results are provided to validate these analytical solutions. The analytical and numerical solutions are essentially identical for these high Knudsen number jet flows.
