Design and application of a novel Laser-Doppler Velocimeter for turbulence structural measurements in turbulent boundary layers

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dc.contributor.authorLowe, K. Todden
dc.contributor.committeechairSimpson, Roger L.en
dc.contributor.committeememberMarchman, James F. IIIen
dc.contributor.committeememberWicks, Alfred L.en
dc.contributor.committeememberDevenport, William J.en
dc.contributor.committeememberRagab, Saad A.en
dc.contributor.departmentAerospace and Ocean Engineeringen
dc.date.accessioned2014-03-14T20:17:20Zen
dc.date.adate2006-11-20en
dc.date.available2014-03-14T20:17:20Zen
dc.date.issued2006-09-18en
dc.date.rdate2008-11-20en
dc.date.sdate2006-10-12en
dc.description.abstractAn advanced laser-Doppler velocimeter is designed to acquire fully-resolved turbulence structural measurements in high Reynolds number two- and three-dimensional turbulent boundary layers. The new instrument combines, for the first time, new techniques allowing for the direct measurement of particle acceleration and sub-measurement-volume-scale position resolution so that second-order 3D particle trajectories may be measured at high repetitions. Using these measurements, several terms in the Reynolds stress transport equations may be directly estimated, giving new data for modeling and understanding the processes leading to the transport of turbulence in boundary layer flows. Due to the unique performance of the probe, many aspects of LDV instrumentation development were addressed. The LDV configuration was optimized for lowest uncertainties by considering the demanding applications of particle position and acceleration measurements. Low noise light detection and signal conditioning was specified for the three electronic channels. A high-throughput data acquisition system allows for exceptional burst rate acquisition. Signal detection and processing algorithms have been implemented which draw from previous techniques but also address distinctive problems with the current system. In short, the instrument was designed to advance the state-of-the-art in LDV systems. Measurements presented include turbulence dissipation rate and fluctuating velocity-pressure gradient correlations that have been measured in 2D and 3D turbulent boundary layers using the unique capabilities of the CompLDV--many of these measurements are the first of their kind ever acquired in high Reynolds number turbulent flows. The flat-plate turbulent boundary layer is studied at several momentum thickness Reynolds numbers up to 7500 to examine Reynolds numbers effects on terms such as the velocity-pressure gradient correlation and the dissipation rate in the Reynolds transport equations. Measurements are also presented in a pressure-driven three-dimensional turbulent boundary layer created upstream from a wing-body junction. The current results complement the extensive data from previous studies and provide even richer depth of knowledge on the most-completely-documented 3D boundary layer flow in existence. Further measurements include the wakes of three circular-cylinder protuberances submerged in a constant pressure turbulent boundary layer.en
dc.description.degreePh. D.en
dc.identifier.otheretd-10122006-105151en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10122006-105151/en
dc.identifier.urihttp://hdl.handle.net/10919/29257en
dc.publisherVirginia Techen
dc.relation.haspartKTL_Dissertation.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectlaser-Doppler velocimetryen
dc.subjectacceleration measurementen
dc.subjectlaser flow diagnosticsen
dc.subjectlaser-Doppler anemometryen
dc.subjectReynolds stress transporten
dc.subjecttransient signal processingen
dc.subjectflow measurement techniquesen
dc.subjectboundary layersen
dc.subjectTurbulenceen
dc.subjectchirp signal processingen
dc.subjectnon-intrusive flow measurementen
dc.titleDesign and application of a novel Laser-Doppler Velocimeter for turbulence structural measurements in turbulent boundary layersen
dc.typeDissertationen
thesis.degree.disciplineAerospace and Ocean Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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