• Login
    View Item 
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Spanwise-nonuniform excitation of a plane mixing layer.

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_td_9127713_sip1_c.pdf
    Size:
    17.28Mb
    Format:
    PDF
    Download
    Author
    Nygaard, Kris Jacob.
    Issue Date
    1991
    Keywords
    Dissertations, Academic
    Mechanical engineering.
    Advisor
    Glezer, Ari
    
    Metadata
    Show full item record
    Publisher
    The University of Arizona.
    Rights
    Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
    Abstract
    The formation and evolution of secondary vortical structures in a plane mixing layer subjected to spanwise-nonuniform excitation has been studied in a closed-return water facility. It is shown that secondary vortices may result from spanwise-nonuniformities in the nominally two-dimensional vorticity layer close to the flow partition, or from spanwise core deformations of the primary vortices further downstream. These distinctly different mechanisms are excited by time-harmonic wavetrains with spanwise amplitude or phase variations, respectively, synthesized by a mosaic of surface film heaters flush-mounted on the flow partition. The appearance of the secondary vortical structures is accompanied by significant distortions in transverse distributions of the streamwise velocity component. Inflection points, which are not present in corresponding velocity distributions of the unforced flow, suggest the formation of locally unstable regions of large shear in which broadband perturbations, already present in the base flow, undergo rapid amplification. This amplification is followed by breakdown to turbulence thus producing the small-scale motion necessary for mixing transition. The present investigation further shows that the flow is extremely receptive to spanwise-periodic amplitude excitation at any wavelength synthesizable by the heater mosaic. Spanwise-periodic phase excitation leads to substantial deformations of the primary vortices, although the receptivity of the flow appears to have a short wavelength cutoff. Spanwise-nonuniform amplitude and phase excitations at a subharmonic frequency of the Kelvin-Helmholtz instability result in complex pairing interactions of the primary vortices.
    Type
    text
    Dissertation-Reproduction (electronic)
    Degree Name
    Ph.D.
    Degree Level
    doctoral
    Degree Program
    Aerospace and Mechanical Engineering
    Graduate College
    Degree Grantor
    University of Arizona
    Collections
    Dissertations

    entitlement

     
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.