The turbulence structure of trailing vortex wakes

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dc.contributor.authorFollin, Gordon J.en
dc.contributor.committeechairDevenport, William J.en
dc.contributor.committeememberNeu, Wayne L.en
dc.contributor.committeememberRagab, Saad A.en
dc.contributor.departmentAerospace Engineeringen
dc.date.accessioned2014-03-14T21:44:22Zen
dc.date.adate2008-09-04en
dc.date.available2014-03-14T21:44:22Zen
dc.date.issued1996-07-19en
dc.date.rdate2008-09-04en
dc.date.sdate2008-09-04en
dc.description.abstractThe present investigation is a two-part study of the mean flow and turbulence structure of isolated vortices and counter-rotating vortex pairs. In the first part, the turbulence structure of an isolated vortex was studied using three-component velocity measurements. Vortices were generated using two symmetrical airfoils. Measurements were made in cross-sectional grids and profiles over a range of Reynolds numbers and downstream distances. Contours of axial normal stress were high-pass filtered to remove the contributions of wandering to the velocity fluctuations. This process reveals a vortex core which is laminar and is surrounded by a region of high turbulence. Core velocity profiles reveal that maximum tangential velocity increases with Reynolds number and decreases with distance downstream. Core radius increases with distance downstream and decreases with Reynolds number. In the second part, flow visualizations of the wake behind a delta wing model were made for a range of Reynolds numbers and lift coefficients. These visualizations reveal the near-instantaneous turbulence structure of the wing wake which is dominated by a vortex pair and a connecting "braid" wake. The braid spacing decreases with increasing Reynolds number and is independent of lift coefficient. The extent of the braid downstream of the wing increases with lift coefficient and decreases with increasing Reynolds number. The large turbulence scales in the wing wake were found to increase in discrete jumps indicating some sort of reorganization of turbulence such as pairing. This reorganization of turbulence was found to occur more quickly as Reynolds number is increased.en
dc.description.degreeMaster of Scienceen
dc.format.extentxviii, 230 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-09042008-063119en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-09042008-063119/en
dc.identifier.urihttp://hdl.handle.net/10919/44520en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1996.F655.pdfen
dc.relation.isformatofOCLC# 35645209en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjecthot-wireen
dc.subjectTurbulenceen
dc.subjectflow visualizationen
dc.subjectvortexen
dc.subjectdelta wingen
dc.subject.lccLD5655.V855 1996.F655en
dc.titleThe turbulence structure of trailing vortex wakesen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineAerospace Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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