The results of computational simulations may supplement MR and other *in vivo* diagnostic techniques to provide an accurate picture of the hemodynamics in particular vessels, which may help demonstrate the risks of embolism or plaque rupture posed by particular plaque deposits. In this study, a model based on an endarterectomy specimen of the plaque in a carotid bifurcation was examined. The flow conditions include steady flow at Reynolds numbers of 300, 600, and 900 as well as unsteady, pulsatile flow. Both dynamic pressure and wall shear stress are very high, with shear values up to $70\u200aN/m2,$ proximal to the stenosis throat in the internal carotid artery, and both vary significantly through the flow cycle. The wall shear stress gradient is also strong along the throat. Vortex shedding is observed downstream of the most severe occlusion. Two turbulence models, the Chien and Goldberg varieties of $k-\epsilon ,$ are tested and evaluated for their relevance in this geometry. The Chien model better captures phenomena such as vortex shedding. The flow distal to stenosis is likely transitional, so a model that captures both laminar and turbulent behavior is needed.

*Computers in Cardiology*, A. Murray and R. Arzbaecher, eds., IEEE, pp. 109–112.

*Numerical Simulations of Blood Flow Through the Carotid Artery Bifurcation*, Ph.D. thesis, University of California, Berkeley.

*Cardiovascular Fluid Dynamics*,

**Vol. 2**, D. H. Bergel, ed., Academic Press, London, pp. 111–139.

*Biodynamics: Circulation*, Springer, New York.

*An Introduction to Biorheology*, Elsevier, Amsterdam.

*Cardiovascular Flow Dynamics and Measurements*, N. H. C. Hwang and N. A. Normann, eds., University Park Press, Baltimore, pp. 799–823.

*Steady Laminar and Turbulent Flow Through Vascular Stenoses Models*, Ph.D. thesis, Georgia Institute of Technology, Atlanta.