An examination of flow characteristics in collapsing elastic tubes

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dc.contributor.authorDavis, Roy Benjaminen
dc.contributor.committeechairSchneck, Daniel J.en
dc.contributor.committeememberFrederick, Danielen
dc.contributor.committeememberBaird, Donald G.en
dc.contributor.committeememberGrant, J. Wallaceen
dc.contributor.committeememberGutstein, W.H.en
dc.contributor.committeememberKraige, Lutheren
dc.contributor.committeememberSmith, C.W.en
dc.contributor.departmentEngineering Mechanicsen
dc.date.accessioned2017-03-10T15:14:56Zen
dc.date.available2017-03-10T15:14:56Zen
dc.date.issued1983en
dc.description.abstractA 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.en
dc.description.degreePh. D.en
dc.format.extentxiv, 177 leavesen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/10919/76051en
dc.language.isoen_USen
dc.publisherVirginia Polytechnic Institute and State Universityen
dc.relation.isformatofOCLC# 10762325en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1983.D385en
dc.subject.lcshCoronary arteries -- Modelsen
dc.subject.lcshBiomedical engineeringen
dc.subject.lcshFlow visualizationen
dc.titleAn examination of flow characteristics in collapsing elastic tubesen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineEngineering Mechanicsen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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