Thesis (Ph. D.)--University of London, 1983. / Includes bibliographical references (p. [375]-400) and index.

No description available.

Three-dimensional (3D) turbulent boundary layers (TBLs) are ubiquitous in most engineering applications, but most turbulence models used to simulate these flows are built on two-dimensional turbulence theory, limiting the accuracy of simulation results. To improve the accuracy of turbulence modeling capabilities, a better understanding of 3DTBL physics is required. This dissertation outlines the experimental investigation of the attached 3D TBL flow over the Benchmark Validation Experiments for RANS/LES Investigations (BeVERLI) Hill using laser Doppler velocimetry in the Virginia Tech Stability Wind Tunnel. The mean flow and turbulence behavior of the boundary layer are studied and compared with turbulence theories to identify the validity of these assumptions in the BeVERLI Hill flow. It is shown that the pressure gradients and curvature of the hill have a significant effect on the turbulence behavior, including significant history effects at all stations due to the changing pressure gradient impact through the height of the boundary layer. Supplementing the experimental results with analysis from rapid distortion theory and simulations, it is shown that the stations lower on the hill are significantly affected by the non-linear history effects due to the varying upstream origins of the flow passing through those stations. Stations closer to the hill apex pass through a region of extremely strong favorable pressure gradient and hill constriction, resulting in behavior that matches qualitatively with the results from rapid distortion theory and provides insights into the physical mechanisms taking place in these regions of the flow. Despite the misalignment of the mean flow angle (γ_FGA) and turbulent shear stress angle (γ_SSA) throughout all of the profiles, the proposed 3D law of the wall of van den Berg (1975), which incorporates pressure gradient and inertial effects and relies on the assumption that γ_FGA=γ_SSA, is able to predict the flow behavior at more mildly non-equilibrium stations. This suggests that models that currently rely on assumptions founded on the two-dimensional law of the wall could be improved by incorporating van den Berg's model instead. The total shear stress distribution at selected stations on the BeVERLI Hill are all significantly reduced below equilibrium two-dimensional (2D) levels, indicating that turbulence models built on this assumptions will not be able to accurately simulate the 3D turbulence behavior. / Doctor of Philosophy / As an object moves through a fluid or a fluid moves past an obstacle, fluid sticks to the solid boundary of the object because of the fluid's viscosity, resulting in zero velocity on the surface (known as the "no-slip" condition). There then exists a region where the flow velocity increases from zero to the freestream velocity - this region is known as the boundary layer. The nature of the boundary layer developing around a body significantly influences how the body and fluid interact and is critical to practical items of engineering interest, such as estimating how much drag a vehicle will experience. Most bodies of engineering interest are three-dimensional (3D), like an aircraft or a car, and thus induce a three-dimensional boundary layer, but many turbulence theories used in computational fluid dynamics simulations are based on simplified two-dimensional (2D) flow behavior studied in laboratories. To further improve the accuracy of simulations, a better understanding of three-dimensional turbulent boundary layer flows is required. This dissertation outlines a study of three-dimensional turbulent flows by analyzing the three-dimensional turbulent boundary layer over the Benchmark Validation Experiments for RANS/LES Investigations (BeVERLI) Hill using laser Doppler velocimetry (LDV) in the Virginia Tech Stability Wind Tunnel. LDV uses the Doppler shift principle to measure the fluid velocity and turbulence at different points in the flow. Through analysis of the fluid velocity and turbulence in the flow, it is shown that the turbulence and flow behavior at certain stations are heavily influenced on the upstream flow history. Stations closer to the bottom of the hill are more influenced by the upstream flow history, while stations closer to the top of the hill experience such strong acceleration due to the local favorable pressure gradient and hill curvature that the upstream history has a more linear influence. In general, the turbulence on the hill is reduced due to the acceleration over the surface below 2D levels and does not match with the 2D fundamental relationships often used in turbulence theories for simulations. Thus, simulations that rely on these assumptions will not be able to accurately predict the details of the 3D flow. A proposed 3D model for the mean velocity behavior by van den Berg (1975) will perform better in simulations than the typical 2D law used in some turbulence model assumptions.

No description available.

Strawberry Hill, the Gothic villa and associated landscape, seat of Horace Walpole (1717-97), is without doubt mandatory in any assessment of eighteenth-century British architecture, yet the reasons for its creation have never been adequately explained or fully understood. This thesis asserts, for the first time, that Walpole’s ideas which informed Strawberry Hill are inspired by theories that stimulate ‘The Pleasures of the Imagination’ as articulated in essays by Joseph Addison (1672-1719) published in the Spectator (1712). The thesis argues that Walpole’s reasons for choosing Gothic have been misunderstood and that he valued this ‘true’ style of British architecture for its associative and imaginative connotations and as a means of expressing historical interpretation through material objects. It affirms that Strawberry Hill expressed the idea that it was based on monastic foundations using architectural quotations from Gothic tombs, representing visual links to historical figures and events. The thesis, moreover, develops an argument as to how Walpole’s theories expressed in Anecdotes of Painting (1762-71) and The History of the Modern Taste in Gardening (1780) became manifest at Strawberry Hill. Avoiding the straightforward architectural description of previous texts, the thesis demonstrates Strawberry Hill to be a sequence of theatrical spaces playing with scale, colour and atmosphere, specifically designed to create surprise and wonder in order to stimulate the imagination. A series of sensory effects and moods, based on contemporary landscape theory, create a background to Walpole’s collection of cultural and historical artefacts – each ‘singular,’ ‘unique,’ or ‘rare’ - artfully displayed to produce their own narrative. Unlike previous studies, the villa and landscape are evaluated as an entity, a structured essay in associative, imaginative thought. Finally, the dissertation reconstructs Strawberry Hill as it existed in Horace Walpole’s time, leading the reader on an integrative virtual tour of buildings, gardens, emblematic models and associative inspirations.

Zugl.: Mainz, Univ., Magisterarbeit, 2005

Zugl.: Mainz, Univ., Magisterarbeit, 2005.

Thesis (M.A.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.) -- Brigham Young University. Dept. of Religion, 1956.

Thesis (M.S.) -- Brigham Young University. Dept. of Religion, 1956. / Electronic thesis. Also available in print ed.