An Experimental Fluid dynamics Study of Exact-Replica Atherosclerotic Carotid Bifurcations
Abstract
Physiological flow studies are carried out in two different models of atherosclerotic carotid bifurcations using flow visualization and particle image velocimetry (PIV). The flow models exactly replicate the lumen of plaques excised intact from patients with severe atherosclerosis. A boundary treatment technique is employed in PIV processing to estimate the flow strain rate near the wall, hence to estimate the wall shear stresses (WSS) to a first order accuracy. The systolic and diastolic Reynolds numbers are about 900 and 300, respectively, which match Doppler Ultrasound scans done on the patients just before surgery. The complex internal geometry of the diseased artery combined with the pulsatile input flows gives exceedingly complex flow patterns. The flows are highly three-dimensional and chaotic in which the details vary from cycle to cycle. The flow patterns include internal jets, three-dimensional shear layers, stagnation lines, separation zones and recirculation zones. The vorticity and streamline maps confirm the highly complex and three-dimensional nature of the flow. WSS are estimated to range from -7 Pa to 30 Pa at the stenotic neck over time. Companion experiments are also carried out with sinusoidal and steady CCA input flows for comparison.
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- November 2003
- Bibcode:
- 2003APS..DFD.JE011B