IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 15, Issue 1 Ver. IV (Jan. - Feb. 2018), PP 33-43 www.iosrjournals.org DOI: 10.9790/1684-1501043343 www.iosrjournals.org 33 | Page Simulation of Physiological Non-Newtonian Blood Flow through 3-D Geometry of Carotid Artery with Stenosis Khairuzzaman Mamun 1 , Most. Nasrin Akhter 2 , and Ken-ichi Funazaki 1 1(Mechanical Engineering Department, Iwate University, Morioka, Iwate, Japan) 2(Department of Mathematics, Dhaka University of Engineering and Technology, Gazipur-1700, Bangladesh) Corresponding Author: Khairuzzaman Mamun Abstract: A numerical simulation has been performed to investigate blood flow behavior of three dimensional idealized carotid arteries. Non-Newtonian flow has been taken for the simulation. The wall of the vessel is considered to be rigid. Physiological and parabolic velocity profile has been imposed for inlet boundary condition. Reynolds number at the inlet has been ranged approximately from 86 to 966 for the investigation. Low Reynolds number k-w model has been used as governing equation. The investigations have been carried out to characterize the flow behavior of blood. The numerical results have been presented in terms of wall shear stress distributions, streamlines contours and axial velocity contours. However, highest wall shear stress has been observed in the bifurcation area. Unexpectedly, transient or unstable flow has created flow disturbance regions in the arteries. Moreover, the disturbance of flow has risen as the severity of stenosis in the artery has been increased. Keywords - Atherosclerosis, Carotid artery, Physiological flow, Stenosis, Viscoelastic fluid --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 09-02-2018 Date of acceptance: 24-02-2018 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction The carotid arteries are located on both side of the neck, the blood vessels that carry oxygenated blood to the head, brain and face. Actually, they supply essential oxygenated blood to the large front part of the brain which controls thought, speech, personality as well as our sensory (our ability to feel) and motor (our ability to move) functions. Besides, the brain survives on a continuous supply of oxygen and glucose carried by blood through it. Thus, Carotid artery disease such as stenosis in the carotid artery can cause cerebral disturbance. However, stenosis in the artery is an abnormal constriction of the artery. Generally, arteries are strong and flexible blood vessels that can expand and contract with heartbeats. They contain endothelium (a thin layer of cells) that keeps the artery smooth and allows blood to flow easily. However, the endothelium becomes damaged by accumulating Lower Density Lipoprotein (LDL cholesterol) in the artery wall. On the other hand, the body sends macrophage white blood cells to clean up the cholesterol, but sometimes the cells get stuck there and gradually build up plaque with bad cholesterol (LDL cholesterol) at the affected site. Thus, the arterial wall loses its flexibility which decreases the area of artery which is called arterial stenosis. The initial research on blood flow within stenosed arteries concentrated on experimental simulations. Smith [1] conducted extensive studies of steady flows through an axisymmetric stenosed artery using an analytical approach where he revealed that the resulting flow patterns were highly dependent on geometry of the stenosis and the overall Reynolds number of the flow. Another study investigated by Deshpande et al [2] depicted the finite difference scheme to solve the flow through an axisymmetric stenosis under steady flow and arrived at similar conclusions. An investigation by Young and Tsai [3] provided experimental analysis on steady flow through stenosed arteries with varying severity, stenosis length, axisymmetric and asymmetric conditions, and with a range of Reynolds numbers from laminar to turbulent flows. It was found that all these factors contributed significantly to the flow behavior. As expected, low fluid Reynolds number, smooth stenosis transitions and low degrees of severity tended to have little effect on the flow. Later studies have shown that in order to approach realistic conditions, it is not possible to neglect the time-varying nature of the flow within the arteries. Other studies have thus included transient conditions into their simulations in order to take into account this flow behavior. Imaeda and Goodman [4] performed simulations on non-linear pulsatile blood flow in large arteries to determine the stability of the code and model used as well as to provide a proper representation of higher-frequency components. In addition, this code attempted to account for the viscoelastic properties of the wall in terms of wall motion and the effect on the fluid. Misra and Chakravaty [5] also performed simulations of arteries incorporating stenosis and assuming blood as a Newtonian fluid. The effect of artery wall response was also incorporated into the simulation and fluid harmonic waves were studied. Young and Tsai [6] further extended their previous experiment to include oscillation flows with the aim of deriving an equation to describe