SHEAR-STRESS AT A COMPLIANT MODEL OF THE HUMAN CAROTID BIFURCATION

To investigate the role of a compliant wall to the near wall hemodynam ic flowfield, two models of the carotid bifurcation were constructed. Both were of identical infernal geometries, however, one was made of c ompliant material which produced approximately the same degree of wall motion as that occurring in vivo while the other one was rigid. The i nner geometries were formed from the same mold so that the configurati ons are directly comparable. Each model was placed in a pulsatile flow system that produced a physiologic flow waveform. Velocity was measur ed with a single component Laser system and wall shear rate was estima ted from near wall data. Wall motion in the compliant model was measur ed by a wall motion transducer and the maximum diameter change varied between 4-7 percent in the model with the greatest change at the axis intersection. The mean shear stress in the compliant model was observe d to be smaller by about 30 percent at most locations. The variation i n peak shear stress was greater and occasionally reached as much as 10 0 percent with the compliant model consistently having smaller positiv e and negative peaks. The separation point was seen to move further up stream in the compliant cast. The modified flowfield in the presence o f a compliant wall can then be important in the hemodynamic theory of atherogenesis.