Unsteady stenosis flow prediction: a comparative study of non-Newtonian models with operator splitting scheme

This paper presents a comparative study of non-Newtonian and Newtonian mode ls of blood. A non-Newtonian incompressible 2-D Navier-Stokes (N-S) solver has been developed using Fasttalk language within the Fastflo environment. It is based on the method of operator splitting with artificial compressibi lity technique. The Power law and Casson models have been used as the const itutive equations for blood with a hematocrit of approximately 45%. These t wo non-Newtonian models and the Newtonian model are used to simulate unstea dy flow through a hypothetical stenotic geometry over an aperiodic time int erval of 1 s. Through comparison of the results of the three models, it was found that the wall shear stress (WSS) distribution over the time interval was comparable for both non-Newtonian models. The peak WSS for the Newtoni an model had the lowest value. The peak wall shear stress gradient (WSSG) f or the Power law was the highest, followed by the Casson and Newtonian mode ls. Flow characteristics such as higher pressure drop across the stenosis, location and movement of vortex were similar in all three models. Non-Newto nian effects were most significant in the vicinity of the stenosis. (C) 200 0 IPEM. Published by Elsevier Science Ltd. All rights reserved.