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The development of solution algorithms for compressible flows /Slack, David Christopher, January 1991 (has links)
Thesis (Ph. D.)Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 130134). Also available via the Internet.

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Magnetically assisted liquidsolid fluidization in a gradient magnetic field : theory and applicationSornchamni, Thana 18 March 2004 (has links)
Graduation date: 2004

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Fluid dynamic means of varying the thrust vector from an axisymmetric nozzle / submitted by Steven Slavko Vidakovic.Vidakovic, Steven Slavko January 1995 (has links)
Bibliography: leaves 190212. / xxiii, 240 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis describes a thrust vectoring nozzle (TVN) which produces a jet which may be deflected at angles in excess of 80o from the nozzle axis by fluid dynamic means, while maintaining total thrust efficiency of the order of 50%, or at 50o with an efficiency of the order of 70%. The thrust vectoring by fluid dynamic means is achieved by injecting secondary fluid at the nozzle throat and partially separating the primary jet causing it to deform. / Thesis (Ph.D.)University of Adelaide, Dept. of Mechanical Engineering, 1995

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Topics on spatially highorder accurate methods and preconditioning for the NavierStokes equations with finiterate chemistry /Godfrey, Andrew Grady, January 1992 (has links)
Thesis (Ph. D.)Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 209216). Also available via the Internet.

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The development of solution algorithms for compressible flowsSlack, David Christopher 28 July 2008 (has links)
This work investigates three main topics. The first of these is the development and comparison of time integration schemes on twodimensional unstructured meshes. Both explicit and implicit solution algorithms for the twodimensional Euler equations on unstructured grids are presented. Cellcentered and cellvertex finite volume upwind schemes utilizing Roe’s approximate Riemann solver are developed. For the cellvertex scheme, a four stage RungeKutta time integration with and without implicit residual averaging, a point Jacobi method, a symmetric point GaussSeidel method, and two methods utilizing preconditioned sparse matrix solvers are investigated. For the cellcentered scheme, a RungeKutta scheme, an implicit tridiagonal relaxation scheme modeled after line GaussSeidel, a fully implicit LU decomposition, and a hybrid scheme utilizing both RungeKutta and LU methods are presented. A reverse CuthillMcKee renumbering scheme is employed for the direct solver in order to decrease CPU time by reducing the fill of the Jacobian matrix. Comparisons are made for both firstorder and higherorder accurate solutions using several different time integration algorithms. Higherorder accuracy is achieved by using multidimensional monotone linear reconstruction procedures. Results for flow over a transonic circular arc are compared for the various time integration methods. The second topic involves an interactive adaptive remeshing algorithm. The interactive adaptive remeshing algorithm utilizing a frontal grid generator is compared to a single grid calculation. Several device dependent interactive graphics interfaces have been developed along with a device independent DI3000 interface which can be employed on any computer that has the supporting software including the Cray2 supercomputers Voyager and Navier. Solutions for twodimensional, inviscid flow over a transonic circular arc and a Mach 3.0 internal flow with an area change are examined. The final topic examined in this work is the capabilities developed for a structured threedimensional code called GASP. The capabilities include: generalized chemistry and thermodynamic modeling, space marching, memory management through the use of binary C Input/Output, and algebraic and twoequation eddy viscosity turbulence modeling. Results are given for a Mach 1.7 threedimensional analytic forebody, a Mach 1.38 axisymmetric nozzle with hydrogenair combustion, a Mach 14.1 15° ramp, and Mach 0.3 viscous flow over a flat plate. The incorporation of these capabilities and the twodimensional unstructured time integration schemes into a threedimensional unstructured solver is also discussed. / Ph. D.

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Numerical investigation of physical vapor and particulate transport under microgravity conditionsTebbe, Patrick A. January 1997 (has links)
Thesis (Ph. D.)University of MissouriColumbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 107110). Also available on the Internet.

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Numerical investigation of physical vapor and particulate transport under microgravity conditions /Tebbe, Patrick A. January 1997 (has links)
Thesis (Ph. D.)University of MissouriColumbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 107110). Also available on the Internet.

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Topics on spatially highorder accurate methods and preconditioning for the NavierStokes equations with finiterate chemistryGodfrey, Andrew Grady 06 June 2008 (has links)
This dissertation discusses two aspects of computational fluid dynamics: high order spatial accuracy and convergencerate acceleration through system preconditioning. Concerning highorder accuracy, the computational qualities of various spatial methods for the finitevolume solution of the Euler equations are presented. The twodimensional essentially nonoscillatory (ENO), kexact, and dimensionally split ENO reconstruction operators are discussed and compared in terms of reconstruction and solution accuracy and computational cost. Standard variable extrapolation methods are included for completeness. Inherent steadystate convergence difficulties are demonstrated for adaptivestencil algorithms. Methods for reconstruction error analysis are presented and an exact solution to the heat equation is used as an example. Numerical experiments presented include the Ringleb flow for numerical accuracy and a shockreflection problem. A vortexshock interaction demonstrates the ability of the EN 0 scheme to excel in capturing unsteady highfrequency flow physics.
Concerning convergencerate acceleration, characteristicwave preconditioning is extended to include generalized finiterate chemistry with nonequilibrium thermodynamics Additionally, the proper preconditioning for the onedimensional NavierStokes equations is presented. Eigenvalue stiffness is resolved and convergencerate acceleration is demonstrated over the entire Machnumber range from the incompressible to the hypersonic. Specific benefits are realized at low and transonic flow speeds. The extended preconditioning matrix accounts for thermal and chemical nonequilibrium and its implementation is explained for both explicit and implicit time marching. The effects of highorder spatial accuracy and various flux splittings are investigated. Numerical analysis reveals the possible theoretical improvements from using preconditioning at all Mach numbers. Numerical results confirm the expectations from the analysis. The preconditioning matrix is applied with dual time stepping to obtain arbitrarily highorder accurate temporal solutions within an implicit formulation. Representative test cases include flows with previously troublesome embedded highconditionnumber regions. / Ph. D.

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Generalized spatial discretization techniques for spacemarching algorithmsMcGrory, William Dandridge 01 February 2006 (has links)
Two unique spatial discretizations employing generalized indexing strategies suitable for use with spacemarching algorithms are presented for the numerical solution of the equations of fluid dynamics. Both discretizations attempt to improve geometric flexibility as compared to structured indexing strategies and have been formulated while considering the current and future availability of unstructured grid generation techniques. The first discretization employs a generalized indexing strategy utilizing triangular elements in the two dimensions normal to the streamwise direction, while maintaining structure within the streamwise direction. The second discretization subdivides the domain into a collection of computational blocks. Each block has inflow and outflow boundaries suitable for space marching. A completely generalized indexing strategy utilizing tetrahedra is used within each computational block. The solution to the flow in each block is found independently in a fashion similar to the crossflow planes of a structured discretization. Numerical algorithms have been developed for the solution of the governing equations on each of the two proposed discretizations. These spatial discretizations are obtained by applying a characteristicbased, upwind, finite volume scheme for the solution of the Euler equations. Firstorder and higher spatial accuracy is achieved with these implementations. A time dependent, spacemarching algorithm is employed, with explicit time integration for convergence of individual computational blocks. Grid generation techniques suitable for the proposed discretizations are discussed. Applications of these discretization techniques include the high speed flow about a 5° cone, an analytic forebody, and a model SR71 aircraft. / Ph. D.

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