There has been a continuous effort to unveil the physics of hypersonic flows both
experimentally and numerically, in order to achieve an efficient hypersonic vehicle
design. With the advent of the high speed computers, a lot of focus has been given on
research pertaining to numerical approach to understand this physics. The features of
such flows are quite different from those of subsonic, transonic and supersonic ones and
thus normal CFD methodologies fail to capture the high speed flows efficiently. Such
calculations are made even more challenging by the presence of nonequilibrium
thermodynamic and chemical effects. Thus further research in the field of
nonequilibrium thermodynamics is required for the accurate prediction of such high
enthalpy flows.
The objective of this thesis is to develop improved computational tools for
hypersonic aerodynamics accounting for non-equilibrium effects. A survey of the
fundamental theory and mathematical modeling pertaining to modeling high temperature
flow physics is presented. The computational approaches and numerical methods
pertaining to high speed flows are discussed.
In the first part of this work, the fundamental theory and mathematical modeling pertaining to modeling high temperature flow physics is presented. Continuum based
approach (Navier Stokes) and Boltzmann equation based approach (Gas Kinetic) are
discussed. It is shown mathematically that unlike the most popular continuum based
methods, Gas Kinetic method presented in this work satisfies the entropy condition.
In the second part of this work, the computational approaches and numerical
methods pertaining to high speed flows is discussed. In the continuum methods, the
Steger Warming schemes and Roe’s scheme are discussed. The kinetic approach
discussed is the Boltzmann equation with Bhatnagar Gross Krook (BGK) collision
operator.
In the third part, the results from new computational fluid dynamics code developed
are presented. A range of validation and verification test cases are presented. A
comparison of the two common reconstruction techniques: Green Gauss gradient method
and MUSCL scheme are discussed. Two of the most common failings of continuum
based methods: excessive numerical dissipation and carbuncle phenomenon techniques,
are investigated. It is found that for the blunt body problem, Boltzmann BGK method is
free of these failings.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2406 |
| Date | 15 May 2009 |
| Creators | Jain, Sunny |
| Contributors | Girimaji, Sharath |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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