Publications

Abstract not provided.

The Quantum-Kinetic (Q-K) chemical reaction model is implemented in a Navier-Stokes solver, US3D, and tested on the Bow Shock UltraViolet flight experiments. The chemical reaction rates predicted by the Q-K model are compared to a commonly used Park model for flows in thermal non-equilibrium. The results show that in thermal equilibrium the reaction rates between these two models are comparable. The Q-K model predicts greater rates for some chemical reactions and lesser rates for other reactions in an five species air chemistry model. In thermal non-equilibrium, the Q-K model maintains comparable rates near thermal equilibrium, while avoiding issues of strong thermal non-equilibrium seen in the Park model. The application of the Q-K model to the Bow Shock UltraViolet flight experiments show that the model remains consistent with previous Navier-Stokes and DSMC computations over altitudes ranging from 53:5 km up to 87:5 km despite the enforcement of translational-rotational equilibrium. The commonly used Park model was unable to match this performance.

High-frequency pressure sensors were used in conjunction with a high-speed schlieren system to study the growth and breakdown of boundary-layer disturbances into turbulent spots on a 7° cone in the Sandia Hypersonic Wind Tunnel. At Mach 5, intermittent low-frequency disturbances were observed in the schlieren videos. High-frequency secondmode wave packets would develop within these low-frequency disturbances and break down into isolated turbulent spots surrounded by an otherwise smooth, laminar boundary layer. Spanwise pressure measurements showed that these packets have a narrow spanwise extent before they break down. The resulting turbulent fluctuations still had a streaky structure reminiscent of the wave packets. At Mach 8, the boundary layer was dominated by secondmode instabilities that extended much further in the spanwise direction before breaking down into regions of turbulence. The amplitude of the turbulent pressure fluctuations was much lower than those within the second-mode waves. These turbulent patches were surrounded by waves as opposed to the smooth laminar flow seen at Mach 5. At Mach 14, second-mode instability wave packets were also observed. Theses waves had a much lower frequency and larger spanwise extent compared to lower Mach numbers. Only low freestream Reynolds numbers could be obtained, so these waves did not break down into turbulence.

The Quantum-Kinetic (Q-K) chemical reaction model is implemented in a Navier-Stokes solver, US3D, and tested on the Bow Shock UltraViolet flight experiments. The chemical reaction rates predicted by the Q-K model are compared to a commonly used Park model for flows in thermal non-equilibrium. The results show that in thermal equilibrium the reaction rates between these two models are comparable. The Q-K model predicts greater rates for some chemical reactions and lesser rates for other reactions in an five species air chemistry model. In thermal non-equilibrium, the Q-K model maintains comparable rates near thermal equilibrium, while avoiding issues of strong thermal non-equilibrium seen in the Park model. The application of the Q-K model to the Bow Shock UltraViolet flight experiments show that the model remains consistent with previous Navier-Stokes and DSMC computations over altitudes ranging from 53:5 km up to 87:5 km despite the enforcement of translational-rotational equilibrium. The commonly used Park model was unable to match this performance.