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Full-Text Articles in Physical Sciences and Mathematics
Investigation Of Multi-Photon Excitation In Argon With Applications In Hypersonic Flow Diagnostics, Jack L. Mills
Investigation Of Multi-Photon Excitation In Argon With Applications In Hypersonic Flow Diagnostics, Jack L. Mills
Physics Theses & Dissertations
Non-intrusive flow diagnostics are essential for studying the physics of hypersonic flow wake regions. To advance the development of next generation hypersonic vehicles and to improve computational fluid dynamics techniques in the hypersonic regime, NASA needs a suitable non-intrusive diagnostic technique to measure velocity, density, and temperature. We will present our work on developing a seedless, non-intrusive diagnostic technique using excited state argon atoms, prepared via multi-photon excitation. In this dissertation, we report results on the first phase of this hypersonic wake measurement project. In particular, we have redesigned and characterized the performance of a high energy, nanosecond pulsed Ti:Sapphire …
Modeling Shock Waves Using Exponential Interpolation Functions With The Least-Squares Finite Element Method, Bradford Scott Smith Jr.
Modeling Shock Waves Using Exponential Interpolation Functions With The Least-Squares Finite Element Method, Bradford Scott Smith Jr.
Mechanical & Aerospace Engineering Theses & Dissertations
The hypothesis of this research is that exponential interpolation functions will approximate fluid properties at shock waves with less error than polynomial interpolation functions. Exponential interpolation functions are derived for the purpose of modeling sharp gradients. General equations for conservation of mass, momentum, and energy for an inviscid flow of a perfect gas are converted to finite element equations using the least-squares method. Boundary conditions and a mesh adaptation scheme are also presented. An oblique shock reflection problem is used as a benchmark to determine whether or not exponential interpolation provides any advantages over Lagrange polynomial interpolation. Using exponential interpolation …