Virginia Tech
    • Log in
    View Item 
    •   VTechWorks Home
    • ETDs: Virginia Tech Electronic Theses and Dissertations
    • Masters Theses
    • View Item
    •   VTechWorks Home
    • ETDs: Virginia Tech Electronic Theses and Dissertations
    • Masters Theses
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Mean-flow measurements of a turbulent mixing layer from helium slot injection into a supersonic airstream

    Thumbnail
    View/Open
    LD5655.V855_1989.K96.pdf (4.989Mb)
    Downloads: 211
    Date
    1989
    Author
    Kwok, Fei Thomas
    Metadata
    Show full item record
    Abstract
    This investigation studies the mixing in a shear layer developed from helium slot injection into a parallel supersonic airstream and compares the results to those of previous slot-injection tests. The objectives of this study include documenting the helium slot-injection flowfield; providing a baseline for use as a reference for future work; contributing representative and consistent data to the general database; and increasing understanding of shear layer dynamics, especially as a result of foreign-gas injection. The helium injectant exits the slot at y = 1.67, M₋₁ = 1.78, Pu = 0.892 atm, and Tu = 287° K tangentially to an airstream at y = 1.4, M∞= 3, Pt∞= 6.5 atm, and Tt∞= 282° K. The freestream has Re/cm = 5.4x10⁵ and a boundary-layer thickness of (δau/H) = 0.58. The pertinent ratios are (P₁/P∞) = 0.838, (U₁/U∞) = 2, and (P₁/P∞) = 0.1. The slot height H is 1.21 cm. Along with short-duration Schlieren and Shadowgraph photography, concentration, Pitot, cone-static, and stagnation-temperature measurements are taken at each of four streamwise stations (x H = 0.3, 4.2, 10.5, 21.1) to document the development of the mixing layer. ln light of the binary-gas mixture, local concentration information is required to reduce the data to pertinent mean-flow variables (M, p, U, pU, P, and T). As expected, slot injection in general shows poor initial penetration of the injectant into the freestream, and, thus, poor initial mixing. Nevertheless, the helium case shows better mixing than a similar air injection case of a previous experiment, as the mixing shear layer grows 25 percent larger than that in the air case by the last station. Also, about 30 percent more freestream air is entrained into the shear layer in the helium case and is confined mainly to the top third of the mixing layer. The higher mixing rate stems from larger gradients in velocity and density and lower pU values which result in more active transport mechanisms in the helium injection test
    URI
    http://hdl.handle.net/10919/51913
    Collections
    • Masters Theses [19610]

    If you believe that any material in VTechWorks should be removed, please see our policy and procedure for Requesting that Material be Amended or Removed. All takedown requests will be promptly acknowledged and investigated.

    Virginia Tech | University Libraries | Contact Us
     

     

    VTechWorks

    AboutPoliciesHelp

    Browse

    All of VTechWorksCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    Log inRegister

    Statistics

    View Usage Statistics

    If you believe that any material in VTechWorks should be removed, please see our policy and procedure for Requesting that Material be Amended or Removed. All takedown requests will be promptly acknowledged and investigated.

    Virginia Tech | University Libraries | Contact Us