VTechWorks staff will be away for the Thanksgiving holiday beginning at noon on Wednesday, November 27, through Friday, November 29. We will resume normal operations on Monday, December 2. Thank you for your patience.
 

Flow Induced Noise from Turbulent Flow over Steps and Gaps

Simple item page
dc.contributor.authorCatlett, Matthew Ryanen
dc.contributor.committeechairDevenport, William J.en
dc.contributor.committeememberGlegg, Stewart A. L.en
dc.contributor.committeememberSimpson, Roger L.en
dc.contributor.departmentAerospace and Ocean Engineeringen
dc.date.accessioned2014-03-14T20:37:24Zen
dc.date.adate2010-05-26en
dc.date.available2014-03-14T20:37:24Zen
dc.date.issued2010-05-04en
dc.date.rdate2010-05-26en
dc.date.sdate2010-05-17en
dc.description.abstractThe existence of small surface discontinuities on a flow surface generate significant pressure fluctuations which can manifest as radiated far field sound and affect the fluctuating near wall pressure field exerted on the flow surface. A significant amount of research has been performed on various step and gap flows; however few have dealt with step heights that are small relative to the incoming boundary layer. Fewer still have been concerned with measuring the effect on the fluctuating wall pressure field or the radiated far field sound from these small surface discontinuities. This study presents the work aimed at scaling the radiated sound from small forward and backward steps, detailing the surface pressure field as a result of these steps, and detailing the far field sound radiated from gap configurations of similar dimension. These measurements were performed in the Virginia Tech Anechoic Wall Jet facility for step heights that ranged from approximately 10% to 100% of the incoming boundary layer height. The results show the influence of step height and boundary layer velocity on the far field sound from forward and backward steps. Very little directivity is seen for either source and the larger step heights considered in this study are shown to not be acoustically compact. A new mixed scaling normalization is proposed for the far field spectra from both types of step, which is shown to reliably collapse the data. Backward steps are shown to be much weaker producers of far field sound than a similarly sized forward step. The implications of this behavior are discussed with respect to the far field sound measured from various gap flows. The fluctuating wall pressure field was measured upstream and downstream of both step configurations. The data shows a slow recovery of the wall pressure field with lasting disturbances up to 100 step heights downstream of the step feature.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-05172010-192806en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05172010-192806/en
dc.identifier.urihttp://hdl.handle.net/10919/32926en
dc.publisherVirginia Techen
dc.relation.haspartCatlett_MR_T_2010.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectwall jeten
dc.subjectstep noiseen
dc.subjectgap noiseen
dc.subjectsurface pressureen
dc.titleFlow Induced Noise from Turbulent Flow over Steps and Gapsen
dc.typeThesisen
thesis.degree.disciplineAerospace and Ocean Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Catlett_MR_T_2010.pdf
Size:
2.84 MB
Format:
Adobe Portable Document Format
Download

Collections

Masters Theses