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Numerical Studies Of Low Density Two Dimensional Hypersonic Flows By Using The Navier Stokes And Burnett Equations With Nonequilibrium Real Gas Effects
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Book Synopsis Numerical Studies of Low-Density Two-Dimensional Hypersonic Flows by Using the Navier-Stokes and Burnett Equations with Nonequilibrium Real Gas Effects by :
Download or read book Numerical Studies of Low-Density Two-Dimensional Hypersonic Flows by Using the Navier-Stokes and Burnett Equations with Nonequilibrium Real Gas Effects written by and published by . This book was released on 1997 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this research is to study the laminar turbulent transition and other transient flow phenomena of 3-D chemically reacting hypersonic boundary layers by direct numerical simulation (DNS) and by linear stability analysis. The research in the report period was focused on developing new numerical methods for such studies and studying several fundamental transient hypersonic flow phenomena. First, several new efficient and high-order accurate numerical methods for DNS of 3-D hypersonic reacting boundary layers and for computing unsteady hypersonic flows with complex shock interactions were developed. These new methods were developed in order to overcome difficulties associated with the direct numerical simulation of hypersonic flows. Second, several studies on the stability phenomena of hypersonic boundary layers over blunt leading edges both by direct numerical simulation and by linear stability analyses were performed. Also completed were extensive numerical studies on real gas effects on a steady shock/boundary layer interaction and a self-sustained unsteady shock-shock interference heating flows. Third, the effects of using Burnett equations for rarefied hypersonic flow computations were investigated. With the completion of the bulk of work on the development of new numerical methods for complex hypersonic flow simulation, the DNS studies are currently being extended to 3-D hypersonic boundary layer transition over elliptic cross section cones.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Surface Boundary Conditions and Related Technical Issues Concerning Burnett Equations for 2-D Hypersonic Flow by :
Download or read book Surface Boundary Conditions and Related Technical Issues Concerning Burnett Equations for 2-D Hypersonic Flow written by and published by . This book was released on 1994 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on studying steady and transient rarefied hypersonic flow by using the Burnett equations and developing accurate and efficient numerical methods for both the Navier-Stokes and Burnett equations were conducted in three aspects: (1) A new method of formulating the additional boundary conditions for the Burnett equations was presented. The 2-D Burnett equations with first order slip conditions seem to be able to improve the Navier-Stokes equations in two dimensions in the continuum transition regime, though more validation work is needed for the Burnett equations. (2) The first Burnett solutions for axisymmetric flow have been obtained. (3) The high-order ENO schemes have been used to obtain time-accurate solutions of the Navier-Stokes equations to study the unsteady hypersonic shock-shock interference heating on a cylinder. The results show that the inherent unsteadiness has a strong effect on surface heating rates. The ENO schemes were found to work well for numerical simulations of transient hypersonic flow.
Book Synopsis Theoretical Studies of Supersonic Two-dimensional and Axisymmetric Nonequilibrium Flow, Including Calculations of Flow Through a Nozzle by : James Joe Der
Download or read book Theoretical Studies of Supersonic Two-dimensional and Axisymmetric Nonequilibrium Flow, Including Calculations of Flow Through a Nozzle written by James Joe Der and published by . This book was released on 1963 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical and vibrational nonequilibrium phenomena in steady inviscid flow fields are studied by the analysis of flow past curved boundaries. Possible alternative choices of the state variables to be used are considered. General features of the nonequilibrium flow are studied by examination of the mathematical properties of the nonlinear flow equations. An axisymmetric nonequilibrium flow of air through a supersonic nozzle is analyzed by means of numerical computations. The coupling effects between nonuniformity (across a nozzle section) and nonequilibrium, not taken into account in the quasi-one-dimensional flow approximation, are revealed by the present analysis.
Book Synopsis Theoretical and Numerical Studies of Rarefied Hypersonic Flows by : Xionghui Huang
Download or read book Theoretical and Numerical Studies of Rarefied Hypersonic Flows written by Xionghui Huang and published by . This book was released on 2014 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation a comprehensive work on theoretical and numerical studies of rarefied hypersonic flows is presented. On the theoretical part, gaskinetic study and exact solutions are obtained for problems related with high speed collisionless round jet: expanding into a vacuum; impinging at a normally set, diffuse or specular reflective plate with finite radius. Several fundamental geometry-velocity relations are utilized in this study and they play crucial roles. These complete results include flowfield properties, and impingement properties at the plate surface. The final results include complex but accurate integrations involving geometry and specific speed ratio factors. Severals numerical simulations with the direct simulation Monte Carlo method validate these analytical exact results. In the numerical part, a multi-dimensional gas-dynamical computational scheme package GRASP-K ("Generalized Rarefied gAs Simulation Package - Kinetic") is presented. This implementation adopts a concept of simulation engine and it utilizes many Object-Oriented Programming features and software engineering design patterns. As a result, this implementation successfully resolves the problem of functionality and interface conflictions for multi-dimension Gas Kinetic Scheme implementations. The package has an open architecture which benefits further development and code maintenance. This package can utilize traditional structured, unstructured or hybrid grids to model multi-dimensional complex geometries and multi-species hypersonic thermo-chemically non equilibrium gas flows. A preliminary test case of a two-species hypersonic flow passing a cylinder and some preliminary results are obtained. The pressure distribution of the gas mixture along the cylinder wall is compared with those in previous works. A Navier-Stokes equations based computational fluid dynamics solver is also incorporated in the package to simulate hypersonic nonequilibrium flows. This solver includes comprehensive chemical reaction models and thermodynamics relations and the phenolic-silica ablation flow simulation is considered. Finite rate chemical reactions, multiple temperature relaxation processes, and ionization phenomena are modeled. Hence the package can be used to simulate multiple-dimensional, non-equilibrium gas flows with multiple species. Simulation results of several hypersonic gas flows over blunted bodies are presented and compared with results in the literature.
Book Synopsis NAS Technical Summaries: Numerical Aerodynamic Simulation Program, March 1990 - February 1991 by :
Download or read book NAS Technical Summaries: Numerical Aerodynamic Simulation Program, March 1990 - February 1991 written by and published by . This book was released on 1991 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Hypersonic Inviscid Flow by : Wallace D. Hayes
Download or read book Hypersonic Inviscid Flow written by Wallace D. Hayes and published by Courier Corporation. This book was released on 2012-07-13 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unified, self-contained view of nonequilibrium effects, body geometries, and similitudes available in hypersonic flow and thin shock layer; appropriate for graduate-level courses in hypersonic flow theory. 1966 edition.
Book Synopsis Aeronautical Enginnering: A Cumulative Index to a Continuing Bibliography (supplement 312) by :
Download or read book Aeronautical Enginnering: A Cumulative Index to a Continuing Bibliography (supplement 312) written by and published by . This book was released on 1994 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeronautical Engineering written by and published by . This book was released on 1993 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA)
Book Synopsis Effects of Thermochemical Nonequilibrium on Hypersonic Boundary-Layer Instability in the Presence of Surface Ablation Or Isolated Two-Dimensional Roughness by : Clifton Mortensen
Download or read book Effects of Thermochemical Nonequilibrium on Hypersonic Boundary-Layer Instability in the Presence of Surface Ablation Or Isolated Two-Dimensional Roughness written by Clifton Mortensen and published by . This book was released on 2015 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current understanding of the effects of thermochemical nonequilibrium on hypersonic boundary-layer instability still contains uncertainties, and there has been little research into the effects of surface ablation, or two-dimensional roughness, on hypersonic boundary-layer instability. The objective of this work is to study the effects of thermochemical nonequilibrium on hypersonic boundary-layer instability. More specifically, two separate nonequilibrium flow configurations are studied: 1) flows with graphite surface ablation, and 2) flows with isolated two-dimensional surface roughness. These two flow types are studied numerically and theoretically, using direct numerical simulation and linear stability theory, respectively. To study surface ablation, a new high-order shock-fitting method with thermochemical nonequilibrium and finite-rate chemistry boundary conditions for graphite ablation is developed and validated. The method is suitable for direct numerical simulation of boundary-layer transition in a hypersonic real-gas flow with graphite ablation. The new method is validated by comparison with three computational data sets and one set of experimental data. Also, a thermochemical nonequilibrium linear stability theory solver with a gas phase model that includes multiple carbon species, as well as a linearized surface graphite ablation model, is developed and validated. It is validated with previously published linear stability analysis and direct numerical simulation results. A high-order method for discretizing the linear stability equations is used which can easily include high-order boundary conditions. The developed codes are then used to study hypersonic boundary-layer instability for a 7 deg half angle blunt cone at Mach 15.99 and the Reentry F experiment at 100~kft. Multiple simulations are run with the same geometry and freestream conditions to help separate real gas, blowing, and carbon species effects on hypersonic boundary-layer instability. For the case at Mach 15.99, a directly simulated 525~kHz second-mode wave was found to be significantly unstable for the real-gas simulation, while in the ideal-gas simulations, no significant flow instability is seen. An N factor comparison also shows that real-gas effects significantly destabilize the flow when compared to an ideal gas. Blowing is destabilizing for the real gas simulation and has a negligible effect for the ideal gas simulation due to the different locations of instability onset. Notably, carbon species resulting from ablation are shown to slightly stabilize the flow for both cases. For the Reentry F flow conditions, inclusion of the ablating nose cone was shown to increase the region of second mode growth near the nose cone. Away from the nose cone, the second mode was relatively unaffected. Experimental and numerical results have shown that two-dimensional surface roughness can stabilize a hypersonic boundary layer dominated by second-mode instability. It is sought to understand how this physical phenomenon extends from an airflow under a perfect gas assumption to that of a flow in thermochemical nonequilibrium. To these ends, a new high-order shock-fitting method that includes thermochemical nonequilibrium and a cut-cell method, to handle complex geometries unsuitable for structured body-fitted grids, is presented. The new method is designed specifically for direct numerical simulation of hypersonic boundary-layer transition in a hypersonic real-gas flow with arbitrary shaped surface roughness. The new method is validated and shown to perform comparably to a high-order method with a body-fitted grid. For a Mach 10 flow over a flat plate, a two-dimensional roughness element was found to stabilize the second mode when placed downstream of the synchronization location. This result is consistent with previous results for perfect-gas flows. For a Mach 15 flow over a flat plate, a two-dimensional surface roughness element stabilizes the second-mode instability more effectively in a thermochemical nonequilibrium flow, than in a corresponding perfect gas flow.
Book Synopsis Numerical Solutions of the Navier-Stokes Equations for the Supersonic Laminar Flow Over a Two-dimensional Compression Corner by : James Edward Carter
Download or read book Numerical Solutions of the Navier-Stokes Equations for the Supersonic Laminar Flow Over a Two-dimensional Compression Corner written by James Edward Carter and published by . This book was released on 1972 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical solutions have been obtained for the supersonic, laminar flow over a two-dimensional compression corner. These solutions were obtained as steady-state solutions to the unsteady Navier-Stokes equations using the finite-difference method of Brailovskaya, which has the second-order accuracy in the spatial coordinates. Good agreement was obtained between the computed results and the wall pressure distributions measured experimentally by Lewis, Kubota, and Lees for Mach numbers of 4 and 6.06, and respective Reynolds numbers, based on free-stream conditions and the distance from the leading edge to the corner, of 6.8 x 104 and 1.5 x 105. In those calculations, as well as in others, sufficient resolution was obtained to show the streamline pattern in the separation bubble. Upstream boundary conditions to the compression-corner flow were provided by numerically solving the unsteady Navier-Stokes equations for the flat-plate flow field, beginning at the leading edge. The compression-corner flow field was enclosed by a computational boundary with the unknown boundary conditions supplied by extrapolation from internally computed points. Numerical tests were performed to deduce that the magnitude of the errors introduced by the extrapolation was small. Calculations were made to show the effect of ramp angle and wall suction on the interaction flow field. The pressure distributions obtained in the present calculations, including a case of incipient separation, were plotted together by using the free-interaction scaling of Stewartson and Williams. A good correlation of the numerical results was found, but only fair agreement was found between this correlation and the universal pressure distribution found numerically by Stewartson and Williams.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1993 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Perspectives on Hypersonic Viscous and Nonequilibrium Flow Research by : National Aeronaut Administration (Nasa)
Download or read book Perspectives on Hypersonic Viscous and Nonequilibrium Flow Research written by National Aeronaut Administration (Nasa) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-10 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: An attempt is made to reflect on current focuses in certain areas of hypersonic flow research by examining recent works and their issues. Aspects of viscous interaction, flow instability, and nonequilibrium aerothermodynamics pertaining to theoretical interest are focused upon. The field is a diverse one, and many exciting works may have either escaped the writer's notice or been abandoned for the sake of space. Students of hypersonic viscous flow must face the transition problems towards the two opposite ends of the Reynolds or Knudsen number range, which represents two regimes where unresolved fluid/gas dynamic problems abound. Central to the hypersonic flow studies is high-temperature physical gas dynamics; here, a number of issues on modelling the intermolecular potentials and inelastic collisions remain the obstacles to quantitative predictions. Research in combustion and scramjet propulsion will certainly be benefitted by advances in turbulent mixing and new computational fluid dynamics (CFD) strategies on multi-scaled complex reactions. Even for the sake of theoretical development, the lack of pertinent experimental data in the right energy and density ranges is believed to be among the major obstacles to progress in aerothermodynamic research for hypersonic flight. To enable laboratory simulation of nonequilibrium effects anticipated for transatmospheric flight, facilities capable of generating high enthalpy flow at density levels higher than in existing laboratories are needed (Hornung 1988). A new free-piston shock tunnel capable of realizing a test-section stagnation temperature of 10(exp 5) at Reynolds number 50 x 10(exp 6)/cm is being completed and preliminary tests has begun (H. Hornung et al. 1992). Another laboratory study worthy of note as well as theoretical support is the nonequilibrium flow experiment of iodine vapor which has low activation energies for vibrational excitation and dissociation, and can be studied in a laboratory with modest resou...
Book Synopsis Aeronautical Engineering: A Cumulative Index to a Continuing Bibliography (supplement 287) by :
Download or read book Aeronautical Engineering: A Cumulative Index to a Continuing Bibliography (supplement 287) written by and published by . This book was released on 1993 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Hypersonic Flow Theory by : Wallace Hayes
Download or read book Hypersonic Flow Theory written by Wallace Hayes and published by Elsevier. This book was released on 2012-12-02 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypersonic Flow Theory presents the fundamentals of fluid mechanics, focusing on the hypersonic flow theory and approaches in theoretical aerodynamics. This book discusses the assumptions underlying hypersonic flow theory, unified supersonic-hypersonic similitude, two-dimensional and axisymmetric bodies, and circular cylinder. The constant-streamtube-area approximation, streamtube-continuity methods, and tangent-wedge and tangent-cone are also deliberated. This text likewise covers the similar laminar boundary layer solutions, bluntness induced interactions on slender bodies, and free molecule transfer theory. The dynamics of hypersonic flight or hypersonic wing theory, magnetohydrodynamic theory, or any developments involving treatment of the Boltzmann equation are not included. This publication is intended for hypersonic aerodynamicists, students, and researchers conducting work on the hypersonic flow phenomena.
Book Synopsis Hypersonic Nonequilibrium Flow Simulations Over a Blunt Body Using Bgk Simulations by : Sunny Jain
Download or read book Hypersonic Nonequilibrium Flow Simulations Over a Blunt Body Using Bgk Simulations written by Sunny Jain and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
