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    Please use this identifier to cite or link to this item: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/67833


    Title: Estimation of Viscous Dissipative Stresses Induced by a Mechanical Heart Valve Using PIV Data
    Authors: Li, Chi-pei;Lo, Chi-wen;Lu, Po-chien
    Contributors: 淡江大學水資源及環境工程學系
    Keywords: Hemolysis;Turbulent shear stress;Sub-grid scale;Turbulent dissipation;Dynamic equilibrium
    Date: 2010-03
    Issue Date: 2011-10-23 02:06:29 (UTC+8)
    Publisher: New York: Springer New York LLC
    Abstract: Among the clinical complications of mechanical heart valves (MHVs), hemolysis was previously thought to result from Reynolds stresses in turbulent flows. A more recent hypothesis suggests viscous dissipative stresses at spatial scales similar in size to red blood cells may be related to hemolysis in MHVs, but the resolution of current instrumentation is insufficient to measure the smallest eddy sizes. We studied the St. Jude Medical (SJM) 27 mm valve in the aortic position of a pulsatile circulatory mock loop under physiologic conditions with particle image velocimetry (PIV). Assuming a dynamic equilibrium assumption between the resolved and sub-grid-scale (SGS) energy flux, the SGS energy flux was calculated from the strain rate tensor computed from the resolved velocity fields and the SGS stress was determined by the Smagorinsky model, from which the turbulence dissipation rate and then the viscous dissipative stresses were estimated. Our results showed Reynolds stresses up to 80 N/m2 throughout the cardiac cycle, and viscous dissipative stresses below 12 N/m2. The viscous dissipative stresses remain far below the threshold of red blood cell hemolysis, but could potentially damage platelets, implying the need for further study in the phenomenon of MHV hemolytic complications.
    Relation: Annals of Biomedical Engineering 38(3), pp.903-916
    DOI: 10.1007/s10439-009-9867-y
    Appears in Collections:[Graduate Institute & Department of Water Resources and Environmental Engineering] Journal Article

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