Effects of Severity and Dominance of Viscous Force on Stenosis and Aneurysm During Pulsatile Blood Flow Using Computational Modelling

Abstract

Cardiovascular diseases are the predominant cause of the death globally. It has become a challenge for the clinicians to understand the behavior of the stenoses and aneurysms at different stages of the growth. A numerical analysis based on a finite volume approach is employed for a 2-D axisymmetric, incompressible, laminar flow to simulate and compare the pulsatile blood flow in the models of arterial stenosis and aneurysm of the same sizes. Two key parameters, Radial velocity distribution and wall shear stress (WSS) distribution, have been considered for analyzing and comparing stenosis and aneurysm of same sizes of 30% and 50% severity. These parameters have been compared using unsteady blood flow of two frequencies: Womersley number (W0) of 7.75 and 10. In addition, the extent of the effect of Womersley number (W0) has been discussed. A flow input waveform is presented in terms of sinusoid. The results implicate that the Womersley number has a little effect on the flow field when the sizes were varied, which indicates the dominance of viscous force on the flow field of the models considered. It has been observed that the severity of the stenosis or aneurysm has significant effect on the flow field and wall shear stress. It has been concluded that, for a particular depth of stenosis and aneurysm, with the same flow inputs, WSS is significantly high in the stenosis compared to that in aneurysm indicating severe risk in stenosis.

Mathematical Modeling of Unsteady Solute Dispersion in Bingham Fluid Model of Blood Flow Through an Overlapping Stenosed Artery

“…The effect of varying stenosis height and plug core radius on the steady dispersion function, unsteady dispersion function, dispersion function, normalized velocity and mean velocity is analyzed. The range of values of parameters used in this study are as follows: 𝑟 𝑝 : 0-0.2, 𝛿: 0.01-0.3, 𝑙 0 : 3, 𝑑: 2 and 𝑧: 4 [20,24,25]. In this study, Mathematica software is used to generate the results and data for validation and comparison purposes.…”

“…Hossain and Haque [18] and Freidoonimehr et al, [19] claimed that the blockage of a coronary artery with stenosis is highly determined by its shape and degree of stenosis. Meanwhile, [20] using a Newtonian fluid ascribed that the size or the severity of the stenosis has a great impact on the flow field (velocity distribution) and wall shear stress distribution of stenosis.…”

Mathematical Analysis of Unsteady Solute Dispersion with Chemical Reaction Through a Stenosed Artery

“…The present results of H-B fluid with the effect of stenosis and chemical reaction in bloodstream are beneficial to determine the effectiveness of solute dispersion in a narrow stenosed artery and also important to determine the rate of reaction between the blood protein and solute. The range of values of parameters used in this study are as follows: yield stress : p r 0-0.2; power-law index n: 0.95-1.05; rate of chemical reaction parameter  : 0-8 [13,14]. The present results of dispersion coefficient in H-B fluid with the influence of stenosis and chemical reaction has been validated with Jaafar [10] by letting the stenosis height and chemical reaction parameter equal to zero.…”

Flow Characteristics on Carotid Artery Bifurcation of Different Aneurysmal Morphology

“…It not only depends on the geometry and mechanical properties of the artery wall but also depends to an overall pressure difference, and the rheological characteristics of blood such as viscosity and density [14]. Knowledge of this set of parameters at the artery wall allows evaluation of WSS values and thus may provide indications for estimating the risk for development and progression of aneurysm and hemorrhage associated with cerebral aneurysms [14,22].…”