Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 50).

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 291-301).

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 200-205). Available also in a digital version from Dissertation Abstracts.

The work of this thesis is concerned, with the investigation and attempted improvement of an integral method for solving the two dimensional, incompressible laminar boundary layer equations of fluid dynamics. The method which is based on a theoretical two parameter representation of well-known boundary layer properties was first produced by Professor S. N. Curle. Its range of application, reliability and accuracy rely on four universal functions which have been derived from known exact solutions to the boundary layer equations, and are given tabulated in terms of a pressure gradient parameter λ. This thesis seeks to improve these properties by making adjustments to the tabulated functions and also considers the extension of the method to certain compressible boundary layer problems. The first chapter contains the development of, and background to the method and gives a critical assessment of the existing functions. This analysis indicates that the method may be improved by supplying more data for certain ranges of λ from which the functions may be calculated; by improving the fitting process; and by the provision for small values of λ of an analytic form for a shape parameter H which the method involves. To supply more data two new solutions for the flows u₁ = U₀ (1+ξ) and u₁ = u₀ (ξ+ξ³) where ξ is a non-dimensional co-ordinate in the direction of the flow, are investigated. The resulting work produces some interesting examples of the use of series expansions in boundary layer theory and these, and the results produced, are given in the second chapter. The fitting of the functions is carried out in chapter three. Polynomial models in terms of λ are fitted by least squares techniques to data from seven solutions and are adjusted to ensure an analytic form for H for small values of λ. A comparison of results using new and old tables Indicates that an improvement has been made. The transformation relating certain compressible and incompressible flows is next examined and the extension of the method to such problems considered. An idea due to Stewartson for assessing the relative accuracies of methods under such circumstances indicates that the method should be highly accurate, a result confirmed by the calculation of the compressible flow u₁ = u₀ (1-ξ) at a leading edge Mach number of four. The thesis is concluded with a review of the work carried out and the results obtained.

No description available.

The structure of a stable smooth wall zero pressure gradient turbulent boundary layer is investigated experimentally in order to determine the dominant outer region structure and to develop a hypothetical generalized boundary layer flow model. Three hot wire configurations, two vertically separated X-wires and a leading straight wire, a horizontal rake of 5 straight wires, and a vertical rake of 5 straight wires were used in the experiments, conducted at Reɵ = 8200. The basis for data reduction procedures came from crosscorrelations and the Variable Interval Time Average (VITA) technique. Three structure types are reported in the literature to be important: streaks and counter rotating streamwise vorticity, wall scaled hairpins or ring vortices, and large scale (0(ઠ)) bulges. A simple pictorial model consisting of three Reɵ dependent interdeveloping stages, which integrate all three structure types, is presented and discussed in relation to the literature and experiments performed. The rake data indicate that the positive ([formula omitted]u/[formula omitted]t) VITA detected velocity front has a scale much larger than that of the wall scaled eddies which typically have a scale of 100-300 y[formula omitted], and that this velocity front exhibits characteristics that are consistent with the trailing velocity front described in the model. The general convection velocity from basic crosscorrelations and the convection velocity of the positive VITA detected velocity front both had values 90-100% of the local mean velocity over most of the boundary layer. Evidence of small scale structure concentration on the downstream edge of the trailing velocity front is presented. A new method used to determine the average structure inclination angle associated with the trailing velocity front is presented and demonstrates that the generalized structure inclination angle, calculated from basic crosscorrelations between vertically separated sensors, does not indicate structure shape, but is associated with the bulk flow associated with the structure. The new method appears to give results that are consistent with flow visualization and more accurately estimates the inclination angle associated with the most dominant feature of the outer flow, the positive VITA velocity front. Although the model presented is somewhat crude and further development and refinement are required, the model appears to agree with most data in the literature, as well as the present experimental results. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Analytical and numerical analyses along with experimental results are presented for laminar forced convection from a heated flat plate. The heating is of either the constant flux or constant temperature type with a discontinuity in the lateral as well as the free-stream direction. The principal objective was to examine the disturbance created by the lateral discontinuity in heating. Analytical solutions of the boundary layer type relating the wall temperature variation to a specific heat flux distribution were found. These involve Heaviside calculus, Fourier transform techniques and the Lévque velocity approximation, and although formally correct only as the Prandtl number approaches infinity, are found to be fairly accurate for Prandtl numbers as low as unity. Reduction of the energy equation to a two-dimensional elliptic equation by a double similarity transform enabled the calculation of numerical solutions valid in any free-stream cross-section removed from the leading edge. Results for technologically interesting cases of heated strips were found by superposition. The error in assuming such strips to be two-dimensional throughout their lateral extent is calculated. A velocity profile corresponding with the Blasius profile and a cross-sectional temperature field above a wind tunnel model of a heated flat plate were measured with a constant temperature anemometer and a rake of miniature thermocouples respectively. A temperature profile well into the heated portion is of two-dimensional form and the temperature field at the lateral step correlates with a numerical solution. In general, there is good agreement between all three approaches. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Some conductive and convective heat transfer problems with radiative boundary conditions are analysed theoretically. Three specific problems have been analysed. The study has, therefore, been divided into three parts. In Part I the temperature distribution produced in-long, solid circular and rectangular cylinders and a solid sphere in interplanetary space is studied. The solid bodies receive parallel radiation flux on one side and emanate radiant energy to their surroundings at zero degree Rankine. Steady state, constant physical and surface properties, and no heat loss by convection are assumed. Solution of the linear conduction equation with nonlinear boundary conditions is obtained by two approximate, semi-analytical methods, (i) point matching and (ii) least-squares fitting. The results are compared with earlier results obtained by a variational method. The least-squares fit method appears to be most suitable regarding accuracy and simplicity in computation. Its accuracy does not appear to depend appreciably either on the radiation-conduction parameter or on the surface absorptivity. The effect of semi-grayness of the receiving surface is analysed. In Part II the heat transfer characteristics of a circular fin dissipating heat from its surface by convection and radiation are analysed. The temperature is assumed uniform along the base of the fin and constant physical and surface properties are assumed. There is radiant interaction between the fin and its base. Two separate situations are considered. In the first situation heat transfer from the end of the fin is neglected. Solution of the linear conduction equation with nonlinear boundary conditions has been obtained by the least-squares fit method. A solution has also been obtained by the finite difference method and the results compared. Results are presented for a wide range of environmental conditions and physical and surface properties of the fin. In the second situation heat transfer from the end of the fin is also included in the analysis. The solution is obtained by a finite difference procedure. It is shown that neglecting heat transfer from the end is a good approximation for long fins or for fins of high thermal conductivity material. In Part III the problem of laminar heat transfer in a circular tube under radiant heat flux boundary conditions has been analysed. Fully developed velocity profile is assumed and the tube is considered stationary. A steady radiant energy flux is being incident on one half of the tube circumference while the fluid emanates heat through the wall on all sides by radiation to a zero degree temperature environment. A solution by finite difference procedure has been obtained. The temperature distribution and the Nusselt number variation are presented for a wide range of the governing physical parameters. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate