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

    An examination of flow characteristics in collapsing elastic tubes

    Thumbnail
    View/Open
    LD5655.V856_1983.D385.pdf (7.278Mb)
    Downloads: 156
    Date
    1983
    Author
    Davis, Roy Benjamin
    Metadata
    Show full item record
    Abstract
    A hydraulic collapse mechanism was incorporated into a recirculating pulsatile flow system to simulate the physiologic problem cf coronary artery vasospasm. A dimensional analysis of the hemodynamic problem provided the basis for i) the specifications for elastic test sections (both straight and branching), ii) the determination of the flow modelling parameters, Reynolds number and unsteady Reynolds number, and iii) the determination of the dimensionless collapse parameters. The models were collapsed in a controlled manner while changes in volumetric flow rate into and out of the models as well as axial pressure drop were monitored. It was found that the driven collapse of the vessel acts as a pump, the effectiveness of which is dependent on upstream and downstream resistance. There was noted a difference in the volumetric flow curves representing fluid leaving the pre- and the post-collapse models under the same inflow conditions. This was due to both the elastic properties of the models and to the post-collapse shape of the models (curved walls and non-circular cross-section). Time-exposed photographs of tracer particle displacements within the model indicate increased volumetric flow in each branch during the initial phase of the collapse process. Moreover, it was seen that the radial gradient of the axial velocity at each wall surface varied in magnitude (and possibly in sign) during the collapse. The in vitro results do not substantiate the coronary spasm/myocardial ischemia connection, but do further implicate vasospasm as a factor in atherogenesis.
    URI
    http://hdl.handle.net/10919/76051
    Collections
    • Doctoral Dissertations [16358]

    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