Time-resolved PIV measurements of the flow field in a stenosed, compliant arterial model

• Published in: Experiments in fluids Vol. 54; no. 5; pp. 1 - 19
• Main Authors: Geoghegan, P. H., Buchmann, N. A., Soria, J., Jermy, M. C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-05-2013; Springer
• Subjects: Arteries; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Computational fluid dynamics; Constrictions; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Dynamical systems; Engineering; Engineering Fluid Dynamics; Engineering Thermodynamics; Exact sciences and technology; Flow rate; Fluid dynamics; Fluid flow; Fluid- and Aerodynamics; Fundamental areas of phenomenology (including applications); Heat and Mass Transfer; Instability; Instrumentation for fluid dynamics; Medical sciences; Physics; Research Article; Stability; Vortex Ring; Light Sheet; Phase Location; Shear Layer; Particle Image Velocimetry; Carotid; Speed measurement; Stenosis; Flow visualization; Particle image velocimetry; Model test; Hemodynamics; Experimental study; Artery; Blood flow
• ISSN: 0723-4864; 1432-1114
• DOI: 10.1007/s00348-013-1528-0

Compliant (flexible) structures play an important role in several biological flows including the lungs, heart and arteries. Coronary heart disease is caused by a constriction in the artery due to a build-up of atherosclerotic plaque. This plaque is also of major concern in the carotid artery which supplies blood to the brain. Blood flow within these arteries is strongly influenced by the movement of the wall. To study these problems experimentally in vitro, especially using flow visualisation techniques, can be expensive due to the high-intensity and high-repetition rate light sources required. In this work, time-resolved particle image velocimetry using a relatively low-cost light-emitting diode illumination system was applied to the study of a compliant flow phantom representing a stenosed (constricted) carotid artery experiencing a physiologically realistic flow wave. Dynamic similarity between in vivo and in vitro conditions was ensured in phantom construction by matching the distensibility and the elastic wave propagation wavelength and in the fluid system through matching Reynolds (
Re
) and Womersley number (
α
) with a maximum, minimum and mean
Re
of 939, 379 and 632, respectively, and a
α
of 4.54. The stenosis had a symmetric constriction of 50 % by diameter (75 % by area). Once the flow rate reached a critical value, Kelvin–Helmholtz instabilities were observed to occur in the shear layer between the main jet exiting the stenosis and a reverse flow region that occurred at a radial distance of 0.34
D
from the axis of symmetry in the region on interest 0–2.5
D
longitudinally downstream from the stenosis exit. The instability had an axis-symmetric nature, but as peak flow rate was approached this symmetry breaks down producing instability in the flow field. The characteristics of the vortex train were sensitive not only to the instantaneous flow rate, but also to whether the flow was accelerating or decelerating globally.