Hypersonic nonequilibrium flow simulations over a blunt body using bgk simulations

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Title: Hypersonic nonequilibrium flow simulations over a blunt body using bgk simulations
Author: Jain, Sunny
Abstract: 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 .
URI: http : / /hdl .handle .net /1969 .1 /ETD -TAMU -2406
Date: 2009-05-15

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Hypersonic nonequilibrium flow simulations over a blunt body using bgk simulations. Available electronically from http : / /hdl .handle .net /1969 .1 /ETD -TAMU -2406 .

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