Natural convection from a vertical plane surface

PhDTheoretical studies of turbulent natural convection phenomena have for some time been hindered by a lack of any reliable experimental data. The primary objective of this investigation was the provision of such data... Mean velocity and temperature profiles have been measured. These are in general agreement with the only previous results which were obtained in 1921, but show substantial disagreements when compared with theoretical predictions. Distribution of frequency and amplitude in the turbulent temperature fluctuations have also been measured. In addition to the investigation of the turbulent boundary layer, a considerable number of experiments have been carried out on laminar and transitional boundary layers. The work on the laminar boundary layer was prompted by the discovery of the effect of a vertical temperature gradient outside the boundary layer. New similarity solutions to the laminar boundary layer equation have been derived for a wide range of conditions. These solutions suggest that the presence of a temerature gradient outside the boundary layer can cause instability, throughout the whole laminar region. Experimental measurements of local heat transfer rates and temperature profiles tend to confirm the theoretical results. Measurements in a transitional boundary layer show the variation of the local heat-transfer coefficient, together with the development of the mean temperature profiles and the temperature fluctuations. In the derivation of the theoretical results, a new method for the numerical solution of coupled, non-linear differential equations on a digital computer, as been developed. A comparison is made between this method and the more commonly used method of Bunge-Kutta. a

Numerical Simulation of Turbulent Flow Through a Straight Square Duct

Turbulent duct flows are investigated using large eddy simulation at bulk Reynolds numbers, from 4410 to 250,000. Mean secondary flow is found to reveal the existence of two streamwise counter-rotating vortices in each corner of the duct. Turbulence-driven secondary motions that arise in duct flows act to transfer fluid momentum from the centre of the duct to its corners, thereby causing a bulging of the streamwise velocity contours towards the corners. As Reynolds number increases, the ratio of centreline streamwise velocity to the bulk velocity decreases and all turbulent components increase. In addition, the core of the secondary vortex in the lower corner-bisector tends to approach the wall and the corner with increasing Reynolds number. The turbulence intensity profiles for the low Reynolds number flows are quite different from those for the high Reynolds number flows. Typical turbulence structures in duct flows are found to be responsible for the interactions between ejections from wall and this interaction results in the bending of the ejection stems, which indicates that the existence of streaky wall structures is much like in a channel flow

An exploration of supramolecular tape-like assemblies formed by pyridine dicarboxylates

This investigation builds on a previous survey of the solid-state behaviour of pyridinedicarboxylate diesters, an overview of which is presented in Chapter 1. These compounds have been shown to form tape-like assemblies, mediated by a novel triple hydrogen bond motif.Chapter 2 examines the behaviour of a small subset of these compounds in solution, some of which appear to form tape-like aggregates, as studied by 1H NMR spectroscopy. Variable temperature Raman spectroscopy has been used to observe the disruption of the crystal architecture as the sample is heated past its melting point, and the increased strength of the tapes formed by the 2,6-diesters compared to those of the 3,5-analogues has been quantitatively demonstrated by DSC.The results of X-ray diffraction studies on the single crystals of a number of diesters formed with naphthalene and anthracene side-arms are described in Chapter 3. This series of compounds has allowed the effect of changing both the length of the alkyl linker and its position of attachment to the polyaromatic to be considered.The solid-state behaviour of a number of chlorinated and methylated diesters are compared in Chapter 4. Chapter 5 examines the crystal architecture of a number of asymmetrical monoesters and the behaviour of these systems is compared to that of the analogous diesters.Chapter 6 details the progress made towards the use of the 2,6-pyridinedicarboxylate synthon in the synthesis of functional materials. The solid-state behaviour of a number of other pyridine derivatives prepared during the course of the present study is described in Chapter 7.<br/

Active Affections: One or Several Canyons

Our social world is increasingly chaotic. Perhaps there has always been chaos; but our increasingly globalized landscape and information economy seems to place chaos on the frontlines—as videos of military strikes in Iraq, or mundane narratives about making it through another day are available for consumption at any time. Our social world produces. The question: What to do with it all? This dissertation explores the concept of affect, using a collage methodology. To conduct an exploration of affect, which “transpires within and across the subtlest of shuttling intensities” (Seigworth and Gregg 2), this dissertation both explores and performs collage; taking collage as both an artifact for investigation using affect theory, as well as a methodological approach participating in the creation of affect theory. As a result of this commitment, the reader is invited to enter this document in any order they wish—reading directly through, or skipping around chapters as it suits them. As a method, collage operates through placing at least two different things next to each other, and then looking for similarities and differences. Each chapter explores differences by juxtaposing artifacts selected because of a similarity that they shared. Spatial (Harvey Butchart and the Havasupai Native Americans), methodological (the It Gets Better project and Ray Johnson), temporal (September 11, 2001 and September 11, 1973), or praxis-based (Chelsea Manning and Aaron Swartz) similarities guided the juxtaposition of artifacts within each chapter. In addition, each chapter explores a distinct version of affect theory to add to the collage created within and throughout this dissertation. Each chapter is a canyon, collected within the grand canyon of the dissertation as a whole. Ultimately, this dissertation is guided by both academic and artistic impulses. I seek to explore and produce affect theory through deploying the methodology of collage. Drawn to moments that often escape rational interrogation, this dissertation invokes echoes as evidence in order to mobilize a system of resonance through juxtaposition that realizes the power of collage: Establishing interpretive frames that refuse to be finished or fixed. Through the performance of collage methodology, this dissertation seeks to implicitly argue for rhizomatic knowledge systems as a method of resistance to structures of oppression via an aesthetic mobilization of collage

Natural convection from a plane, vertical surface in non-isothermal surroundings

http://deepblue.lib.umich.edu/bitstream/2027.42/4124/5/bac0298.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/4124/4/bac0298.0001.001.tx