The performance of the heart after a valve replacement operation will greatly depend on the flow character downstream the mitral valve thus a better understanding of the flow character is essential. Most in vitro studies of the flow downstream of a MHV have been conducted with the valve in the aortic position. Researchers reported detailed measurements most of which were obtained by Laser Doppler Velocimetry (LDV) in rigid models of the aorta. Digital Particle Image Velocimetry (DPIV) has also been utilized to reveal intricate patterns of interacting shed vortices downstream of the aortic valve. The orientation of the valves may considerably affect the flow development and slight difference may produce significant differences in the ventricular flow fields. Two orientations, respectively anatomical and anti-anatomical, of the St. Jude Medical (SJM) bileaflet valve are presented and compared with the SJM Biocor porcine valve, which served to more closely represent the natural valve. In this effort, we employ a powerful tool to monitor the velocity field in a flexible, transparent LV and study the evolution of large eddies and turbulence through a complete cardiovascular cycle. Both time average and instantaneous results of velocity, vorticity, and turbulent kinetic energy distributions are presented. The presence and location of vortical structures were deduced as well as the level of coherence of these structures. The presence of three distinct flow patterns were identified, by the location of vortical structures and level of coherence, for the three configurations corresponding to significant differences in the turbulence level distribution inside the LV. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/31262 |
| Date | 18 March 2003 |
| Creators | Pierrakos, Olga |
| Contributors | Engineering Science and Mechanics, Pyle, Robert Lee, Berry, Joel, Telionis, Demetri P., Vlachos, Pavlos P. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | application/octet-stream, application/pdf, application/octet-stream, application/octet-stream |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | porcine_velocity.avi, Pierrakos_Thesis.pdf, old_anti_velocity.avi, old_anat_velocity.avi |
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