The effects of gravitational acceleration on micropolar fluid model of blood flow in a bifurcated stenosed artery

Abstract

Gravity is a fundamental force regulating the cardiovascular system in our body. However not many previous studies on bio-fluids take into consideration of the variation of gravitational acceleration. Besides, the geometry of the bifurcated artery is chosen to be investigated since it is significant in human cardiovascular networking, where stenoses tend to form around branching junctions. Blood flow in the segment of artery is assumed to be axisymmetric, unsteady, laminar, fully developed, and two-dimensional. This research investigates the effects of gravity on micropolar fluid model of blood flow along a bifurcated artery segment which consists of a single stenosis at the parent branch. Meanwhile, to proceed with this study, blood is initially modelled as Newtonian fluid and micropolar fluid respectively in a straight stenosed artery segment. Then, the effects of gravity on Newtonian blood flow in bifurcated artery are explored. Here, a non-dimensional parameter G is introduced to describe the condition of gravity, where G is directly proportional to gravitational acceleration. The governing equations are solved numerically using the explicit finite difference method with prescribed condition of pressure and the computational algorithms are developed in Matlab software. Generally, with consideration of gravity variation, increment of gravitational acceleration causes decrement of axial velocity and increment of wall shear stress. Thus the consideration of gravity term in fluid model is necessary so that results obtained are closer to realistic conditions. Further, flow abnormalities are noticed at the branching junction from graphs of wall shear stress. This can be a crucial cause of stenosis overlapping and restenosis, which means that the structures of artery is significant in influencing blood flow patterns.