non-Newtonian Behavior Of Blood Research Articles

Enhancing magnetic drug targeting efficiency through computational analysis: Investigating Particle-RBC interaction and non-newtonian blood behavior

Cancer stands as a foremost global mortality determinant, characterized by a persistent deficit in therapeutic modalities capable of reliably and efficiently conveying anti-cancer pharmaceutical agents to profound tissue loci. Within this context, magnetic drug targeting (MDT) has emerged as an innovative approach to cancer management, offering the promise of minimal adverse effects. Accordingly, the current investigation endeavors to evaluate the capture efficacy (CE) of drug-loaded nanoparticles under the influence of an external magnetic field. To this end, a cylindrical neodymium magnet (NdFeB) is employed as the magnetic source. The finite element method (FEM) was utilized to solve the governing equations. The effect of several parameters, including particle diameter, drag force, blood properties, magnetic field intensity, blood’s non-Newtonian behavior, and particle-RBC interaction on the CE of nanoparticles has been investigated. Simultaneous effect of interaction forces and non-Newtonian behavior of blood on the capturing nanoparticles at the tumor site is considered as the novelty of the present work. Taking into account these two parameters will provide more realistic results. Finding showed that the magnetic field intensity and particles’ diameter positively affect the nanoparticles’ CE. For example, by increasing particle diameter from 250 nm to 1500 nm, the CE is increased from 22 % to 53 %, respectively. In addition, it was revealed that consideration of the particle-red blood cell (RBC) interaction, on average, causes a decrease in the CE of nanoparticles by up to 20 %. Regarding the non-Newtonian behavior of blood, it was found that considering blood as non-Newtonian fluid would decrease, on average, 25 % of CE of nanoparticles compared to Newtonian fluid. Results revealed that simultaneous considering the non-Newtonian behavior of blood and interaction forces significantly affect the CE of nanoparticles.

Thermal transport exploration of ternary hybrid nanofluid flow in a non-Newtonian model with homogeneous-heterogeneous chemical reactions induced by vertical cylinder

Studying the combination of convection and chemical processes in blood flow can have significant applications like understanding physiological processes, drug delivery, biomedical devices, and cardiovascular diseases, and implications for various fields can lead to developing new treatments, devices, and models. This research paper investigates the combined effect of convection, heterogeneous-homogeneous chemical processes, and shear rate on the flow behavior of a ternary hybrid Carreau bio-nanofluid passing through a stenosed artery. The ternary hybrid Carreau bio-nanofluid consists of three different types of nanoparticles dispersed in a Carreau fluid model, miming the non-Newtonian behavior of blood. This assumed study generates a system of PDEs that are processed with similarity transformation and converted into ODEs. Furthermore, these ODEs are solved with bvp4c. The results show that the convection, heterogeneous-homogeneous chemical processes, and shear rate significantly impact the bio-nano fluid’s flow behavior and the stenosed artery’s heat transfer characteristics.

In silico analysis of embolism in cerebral arteries using fluid-structure interaction method

Ischemic stroke, particularly embolic stroke, stands as a significant global contributor to mortality and long-term disabilities. This paper presents a comprehensive simulation of emboli motion through the middle cerebral artery (MCA), a prevalent site for embolic stroke. Our patient-specific computational model integrates major branches of the middle cerebral artery reconstructed from magnetic resonance angiography images, pulsatile flow dynamics, and emboli of varying geometries, sizes, and material properties. The fluid-structure interactions method is employed to simulate deformable emboli motion through the middle cerebral artery, allowing observation of hemodynamic changes in artery branches upon embolus entry. We investigated the impact of embolus presence on shear stress magnitude on artery walls, analyzed the effects of embolus material properties and geometries on embolus trajectory and motion dynamics within the middle cerebral artery. Additionally, we evaluated the non-Newtonian behavior of blood, comparing it with Newtonian blood behavior. Our findings highlight that embolus geometry significantly influences trajectory, motion patterns, and hemodynamics within middle cerebral artery branches. Emboli with visco-hyperelastic material properties experienced higher stresses upon collision with artery walls compared to those with hyperelastic properties. Furthermore, considering blood as a non-Newtonian fluid had notable effects on emboli stresses and trajectories within the artery, particularly during collisions. Notably, the maximum von Mises stress experienced in our study was 21.83 kPa, suggesting a very low probability of emboli breaking during movement, impact, and after coming to a stop. However, in certain situations, the magnitude of shear stress on them exceeded 1 kPa, increasing the likelihood of cracking and disintegration. These results serve as an initial step in anticipating critical clinical conditions arising from arterial embolism in the middle cerebral artery. They provide insights into the biomechanical parameters influencing embolism, contributing to improved clinical decision-making for stroke management.

The Effect of the Non-Newtonian Behavior of Blood on Capture Efficiency of Particles in a Vessel with a Local Symmetrical Stenosis

The Effect of the Non-Newtonian Behavior of Blood on Capture Efficiency of Particles in a Vessel with a Local Symmetrical Stenosis

Computational Multi-Scale Modeling of Drug Delivery into an Anti-Angiogenic Therapy-Treated Tumor.

The present study develops a numerical model, which is the most complex one, in comparison to previous research to investigate drug delivery accompanied by the anti-angiogenesis effect. This paper simulates intravascular blood flow and interstitial fluid flow using a dynamic model. The model accounts for the non-Newtonian behavior of blood and incorporates the adaptation of the diameter of a heterogeneous microvascular network derived from modeling the evolution of endothelial cells toward a circular tumor sprouting from two-parent vessels, with and without imposing the inhibitory effect of angiostatin on a modified discrete angiogenesis model. The average solute exposure and its uniformity in solid tumors of different sizes are studied by numerically solving the convection-diffusion equation. Three different methodologies are considered for simulating anti-angiogenesis: modifying the capillary network, updating the transport properties, and considering both microvasculature and transport properties modifications. It is shown that anti-angiogenic therapy decreases drug wash-out in the periphery of the tumor. Results show the decisive role of microvascular structure, particularly its distribution, and interstitial transport properties modifications induced via vascular normalization on the quality of drug delivery, such that it is improved by 39% in uniformity by the second approach in R = 0.2 cm.

Numerical study of irreversibility analysis on pulsatile flow of blood through a ω-shaped stenotic artery

The mathematical modeling of blood flow in a stenotic blood vessel is very important for understanding the effects of various geometric and rheological parameters on the normal flow of blood. The present study is concerned with the heat and mass transfer in the blood flow of a non-Newtonian fluid through a ω-shaped stenotic arterial segment. The non-Newtonian behavior of blood is described mathematically by employing the constitutive equation of the Herschel-Bulkley fluid. The wall of the artery is considered to be rigid having ω-shaped constriction in its lumen. The mild stenosis assumption is used to simplify the fully coupled momentum, energy, and concentration equations as well as the constitutive equation of the Herschel-Bulkley fluid. Numerical solutions for fluid velocity, temperature, mass concentration, and entropy generation are evaluated by using the explicit finite difference scheme. The effects of various emerging parameters on the velocity, wall shear stress, flow rate, temperature, concentration, and entropy distributions have been analyzed in detail. A comparison between different fluid models has also been presented. It is found that the temperature in the Herschel-Bulkley fluid is marginally lower than that of the Newtonian, Power law, and Bingham fluids whereas an opposite trend is noticed in the case of mass concentration.

Hemodynamic Investigation of the Flow Diverter Treatment of Intracranial Aneurysm

Flow diverter stents (FDS) are increasingly used for the treatment of complex intracranial aneurysms such as fusiform, giant, or wide-neck aneurysms. The primary goal of these devices is to reconstruct the diseased vascular segment by diverting blood flow from the aneurysm. The resulting intra-aneurysmal flow reduction promotes progressive aneurysm thrombosis and healing of the disease. In the present study, a numerical investigation was performed for modeling blood flow inside a patient-specific intracranial aneurysm virtually treated with FDS. The aim of the study is to investigate the effects of FDS placement prior to the actual endovascular treatment and to compare the effectiveness of devices differing in porosity. Numerical simulations were performed under pulsatile flow conditions, taking into account the non-Newtonian behavior of blood. Two possible post-operative conditions with virtual stent deployment were simulated. Hemodynamic parameters were calculated and compared between the pre-operative (no stent placement) and post-operative (virtual stent placement) aneurysm models. FDS placement significantly reduced intra-aneurysmal flow velocity and increased the Relative Residence Time (RRT) on the aneurysm, thus promoting thrombus formation within the dilatation and aneurysm occlusion. The results highlighted an increase in the effectiveness of FDS as its porosity increased. The proposed analysis provides pre-operative knowledge on the impact of FDS on intracranial hemodynamics, allowing the selection of the most effective treatment for the specific patient.

Entropy optimization and response surface methodology of blood hybrid nanofluid flow through composite stenosis artery with magnetized nanoparticles (Au-Ta) for drug delivery application

Entropy creation by a blood-hybrid nanofluid flow with gold-tantalum nanoparticles in a tilted cylindrical artery with composite stenosis under the influence of Joule heating, body acceleration, and thermal radiation is the focus of this research. Using the Sisko fluid model, the non-Newtonian behaviour of blood is investigated. The finite difference (FD) approach is used to solve the equations of motion and entropy for a system subject to certain constraints. The optimal heat transfer rate with respect to radiation, Hartmann number, and nanoparticle volume fraction is calculated using a response surface technique and sensitivity analysis. The impacts of significant parameters such as Hartmann number, angle parameter, nanoparticle volume fraction, body acceleration amplitude, radiation, and Reynolds number on the velocity, temperature, entropy generation, flow rate, shear stress of wall, and heat transfer rate are exhibited via the graphs and tables. Present results disclose that the flow rate profile increase by improving the Womersley number and the opposite nature is noticed in nanoparticle volume fraction. The total entropy generation reduces by improving radiation. The Hartmann number expose a positive sensitivity for all level of nanoparticle volume fraction. The sensitivity analysis revealed that the radiation and nanoparticle volume fraction showed a negative sensitivity for all magnetic field levels. It is seen that the presence of hybrid nanoparticles in the bloodstream leads to a more substantial reduction in the axial velocity of blood compared to Sisko blood. An increase in the volume fraction results in a noticeable decrease in the volumetric flow rate in the axial direction, while higher values of infinite shear rate viscosity lead to a significant reduction in the magnitude of the blood flow pattern. The blood temperature exhibits a linear increase with respect to the volume fraction of hybrid nanoparticles. Specifically, utilizing a hybrid nanofluid with a volume fraction of 3% leads to a 2.01316% higher temperature compared to the base fluid (blood). Similarly, a 5% volume fraction corresponds to a temperature increase of 3.45093%.

Effect of Particle–Particle and RBC–Particle Interactions on Capture Efficiency of Magnetic Nanocarriers Under the Influence of a Nonuniform Magnetic Field

In this study, the capture efficiency (CE) of magnetic carrier particles at the region of interest (ROI) in a micro-vessel was investigated. A nonuniform magnetic field produced by a Nd-Fe-B magnet was applied to capture the carrier particles at the ROI. The particle–particle and red blood cell (RBC)–carrier particle interactions were taken into account. Other parameters including carrier particle diameter, magnetic force, and non-Newtonian behavior of blood were also considered. The finite element method was used to solve the governing equations. Four cases were considered: (1) Newtonian without interaction forces, (2) Newtonian with interaction forces, (3) non-Newtonian without interaction forces, and (4) non-Newtonian with interaction forces. The results showed that for a particle diameter of 2000 nm, the CE values for the case without interaction force and with interaction force were 70% and 53%, respectively. It was found that by considering the particle–particle and RBC–carrier particle interactions for all magnet–vessel distances, the CE of carrier particles decreased, on average, by nearly 19%. At a magnet–vessel distance of 2.5 cm (d=2.5cm),\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$d=2.5\\,\\mathrm{cm}),$$\\end{document} it was seen that the CE values for case 2 and case 3 were nearly 70% and 45%, representing the maximum and minimum CE values, respectively.

Fluid flow and heat transfer in carotid sinuses of different sizes and locations in an open surgery: CFD vs FSI

PurposeAtherosclerosis tends to occur in the distinctive carotid sinus, leading to vascular stenosis and then causing death. The purpose of this paper is to investigate the effect of sinus sizes, positions and hematocrit on blood flow dynamics and heat transfer by different numerical approaches.Design/methodology/approachThe fluid flow and heat transfer in the carotid artery with three different sinus sizes, three different sinus locations and four different hematocrits are studied by both computational fluid dynamics (CFD) and fluid-structure interaction (FSI) methods. An ideal geometric model and temperature-dependent non-Newtonian viscosity are adopted, while the wall heat flux concerning convection, radiation and evaporation is used.FindingsWith increasing sinus size, the average velocity and temperature of the blood fluid decrease, and the area of time average wall shear stress (TAWSS)with small values decreases. As the distances between sinuses and bifurcation points increase, the average temperature and the maximum TAWSS decrease. Atherosclerosis is more likely to develop when the sinuses are enlarged, when the sinuses are far from bifurcation points, or when the hematocrit is relatively large or small. The probability of thrombosis forming and developing becomes larger when the sinus becomes larger and the hematocrit is small enough. The movement of the arterial wall obviously reduces the velocity of blood flow, blood temperature and WSS. This study also suggests that the elastic role of arterial walls cannot be ignored.Originality/valueThe hemodynamics of the internal carotid artery sinus in a carotid artery with a bifurcation structure have been investigated thoroughly, on which the impacts of many factors have been considered, including the non-Newtonian behavior of blood and empirical boundary conditions. The results when the FSI is considered and absent are compared.

Analysis of biological mechanism of blood flow containing nanoparticles through an arterial stenosis

ABSTRACT This article aims to discuss the flow of nanoparticles in the blood through a stenosed artery in the presence of a magnetic field and periodic body acceleration. The overlapping shape of stenosis is chosen to show the impact of blood flow. The Bingham plastic fluid model is utilized to capture the non-Newtonian behavior of blood in the stenosed artery under diseased conditions. The resultant equations are solved analytically using the regular perturbation method. The impact of various emerging parameters on velocity, flow rate, effective viscosity, and wall shear stress are presented through graphs and discussed in detail. It is noticed that liquid velocity and flow rate increase whereas effective viscosity decreases with an increase in slip velocity and Womersley’s frequency parameter. It is also noted that liquid velocity and flow rate are decreased by enhancing the Lorentz force. The increase in body acceleration enhances fluid velocity.

Dynamics of an oscillating microbubble in a blood-like Carreau fluid.

A numerical model for cavitation in blood is developed based on the Keller-Miksis equation for spherical bubble dynamics with the Carreau model to represent the non-Newtonian behavior of blood. Three different pressure waveforms driving the bubble oscillations are considered: a single-cycle Gaussian waveform causing free growth and collapse, a sinusoidal waveform continuously driving the bubble, and a multi-cycle pulse relevant to contrast-enhanced ultrasound. Parameters in the Carreau model are fit to experimental measurements of blood viscosity. In the Carreau model, the relaxation time constant is 5-6 orders of magnitude larger than the Rayleigh collapse time. As a result, non-Newtonian effects do not significantly modify the bubble dynamics but do give rise to variations in the near-field stresses as non-Newtonian behavior is observed at distances 10-100 initial bubble radii away from the bubble wall. For sinusoidal forcing, a scaling relation is found for the maximum non-Newtonian length, as well as for the shear stress, which is 3 orders of magnitude larger than the maximum bubble radius.

Characterizing pulsatile blood flow in a specific carotid bifurcation: insights into hemodynamics and rheology models

<abstract> <p>This study uses laminar and turbulent flow models to investigate the blood flow dynamics in a specific carotid bifurcation. Pulsatile boundary conditions and the rigid carotid artery wall are considered. Three viscosity models describe the non-Newtonian blood behavior. The Fluent solver and the finite volume method solve the equations. Results show a Poiseuille-like flow in the common carotid artery (CCA), unaffected by the flow regime, viscosity model, or boundary conditions. The branching zone exhibits a C-shaped stagnation zone with low velocity and wall shear stress due to the CCA widening and ICA/ECA curvature. Strong secondary flow is observed in the carotid sinus; the flow is directed towards the inner wall with higher velocity in the internal carotid artery. Discrepancies between viscosity models are pronounced in laminar flow, particularly with the natural boundary conditions. The non-Newtonian blood behavior is more apparent in the laminar flow of the external carotid artery, especially with the second set of boundary conditions.</p> </abstract>

Simulation of LDL permeation into multilayer wall of a coronary bifurcation using WSS-dependent model: effects of hemorheology.

Atherosclerosis, due to the permeation of low-density lipoprotein (LDL) particles into the arterial wall, is one of the most common and deadly diseases in today's world. Due to its importance, numerous studies have been conducted on the factors affecting this disease. In this study, using numerical simulation, the effects of Wall Shear Stress (WSS), non-Newtonian behavior of blood, different values of hematocrit and blood pressure on LDL permeation into the arterial wall layers are investigated in a 4-layer wall model of a coronary bifurcation. To obtain the velocity and concentration fields in the fluid domain, the Navier-Stokes, Brinkman, and mass transfer equations are numerically solved in the lumen and wall layers. Results show that it is important to consider the effects of WSS on transport properties of endothelium layer in bifurcations and this leads to completely different concentration profiles compared to the constant properties model. Our computations show that a giant accumulation of LDL in the intima layer of the outer wall of the left anterior descending artery, especially in low WSS regions, may lead to atherosclerosis. It is also, necessary to consider the non-Newtonian behavior of blood in bifurcations due to its direct effect on WSS. A pressure-induced increase in the half-width of leaky junctions may be responsible for the higher risk of atherosclerosis in hypertension. In addition, it is shown that the dominant mechanism in LDL permeation into the wall is convection, and also, hypertension increases the effect of mass transfer by convection mechanism more than the diffusion mechanism. Furthermore, our results are consistent with various clinical studies.

Numerical and experimental investigation of a lighthouse tip drainage cannula used in extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation is a life-saving therapy used in case of acute respiratory/circulatory failure. Exposure of blood to non-physiological surfaces and high shear stresses is related to hemolytic damage and platelet activation. A detailed knowledge of the fluid dynamics of the components under different scenarios is thus paramount to assess the thrombogenicity of the circuit. An investigation of the flow structures developing in a conventional lighthouse tip (single-staged) drainage cannula was performed with cross-validated computational fluid dynamics and particle image velocimetry. The aim was to quantify the variation in drainage performance and stress levels induced by different fluid models, hematocrit and vessel-to-cannula flow rate ratios. The results showed that the 90° bends of the flow through the side holes created a recirculation zone inside the cannula which increased residence time. Flow structures resembling a jet in a crossflow were also observed. The use of different hematocrits did not significantly affect drainage performances. The most proximal set of holes drained the largest fraction of fluid. However, different flow rate ratios altered the flow rate drained through the tip. The use of 2D data led to a 50% underestimation of shear rate levels. In the drainage zone the non-Newtonian behavior of blood was less relevant. The most proximal holes drained the largest amount of fluid. The flow features and distribution of flow rates among the holes showed little dependence on the hematocrit. The non-Newtonian behavior of blood had a small influence on the dynamics of the flow.

Physical Properties of Blood and their Relationship to Clinical Conditions.

It has been long known that blood health heavily influences optimal physiological function. Abnormalities affecting the physical properties of blood have been implicated in the pathogenesis of various disorders, although the exact mechanistic links between hemorheology and clinical disease manifestations remain poorly understood. Often overlooked in current medical practice, perhaps due to the promises offered in the molecular and genetic era, the physical properties of blood which remain a valuable and definitive indicator of circulatory health and disease. Bridging this gap, the current manuscript provides an introduction to hemorheology. It reviews the properties that dictate bulk and microcirculatory flow by systematically dissecting the biomechanics that determine the non-Newtonian behavior of blood. Specifically, the impact of hematocrit, the mechanical properties and tendency of red blood cells to aggregate, and various plasma factors on blood viscosity will be examined. Subsequently, the manner in which the physical properties of blood influence hemodynamics in health and disease is discussed. Special attention is given to disorders such as sickle cell disease, emphasizing the clinical impact of severely abnormal blood rheology. This review expands into concepts that are highly topical; the relation between mechanical stress and intracellular homeostasis is examined through a contemporary cell-signaling lens. Indeed, accumulating evidence demonstrates that nitric oxide is not only transported by erythrocytes, but is locally produced by mechanically-sensitive enzymes, which appears to have intracellular and potentially extracellular effects. Finally, given the importance of shear forces in the developing field of mechanical circulatory support, we review the role of blood rheology in temporary and durable mechanical circulatory support devices, an increasingly utilized method of life support. This review thus provides a comprehensive overview for interested trainees, scientists, and clinicians.

Non-Newtonian Endothelial Shear Stress Simulation: Does It Matter?

Patient-specific coronary endothelial shear stress (ESS) calculations using Newtonian and non-Newtonian rheological models were performed to assess whether the common assumption of Newtonian blood behavior offers similar results to a more realistic but computationally expensive non-Newtonian model. 16 coronary arteries (from 16 patients) were reconstructed from optical coherence tomographic (OCT) imaging. Pulsatile CFD simulations using Newtonian and the Quemada non-Newtonian model were performed. Endothelial shear stress (ESS) and other indices were compared. Exploratory indices including local blood viscosity (LBV) were calculated from non-Newtonian simulation data. Compared to the Newtonian results, the non-Newtonian model estimates significantly higher time-averaged ESS (1.69 (IQR 1.36)Pa versus 1.28 (1.16)Pa, p < 0.001) and ESS gradient (0.90 (1.20)Pa/mm versus 0.74 (1.03)Pa/mm, p < 0.001) throughout the cardiac cycle, under-estimating the low ESS (<1Pa) area (37.20 ± 13.57% versus 50.43 ± 14.16%, 95% CI 11.28–15.18, p < 0.001). Similar results were also found in the idealized artery simulations with non-Newtonian median ESS being higher than the Newtonian median ESS (healthy segments: 0.8238Pa versus 0.6618Pa, p < 0.001 proximal; 0.8179Pa versus 0.6610Pa, p < 0.001 distal; stenotic segments: 0.8196Pa versus 0.6611Pa, p < 0.001 proximal; 0.2546Pa versus 0.2245Pa, p < 0.001 distal) On average, the non-Newtonian model has a LBV of 1.45 times above the Newtonian model with an average peak LBV of 40-fold. Non-Newtonian blood model estimates higher quantitative ESS values than the Newtonian model. Incorporation of non-Newtonian blood behavior may improve the accuracy of ESS measurements. The non-Newtonian model also allows calculation of exploratory viscosity-based hemodynamic indices, such as local blood viscosity, which may offer additional information to detect underlying atherosclerosis.

Effect of Extended Lipid Core on the Hemodynamic Parameters: A Fluid-Structure Interaction Approach.

Myocardial infarction is one of the leading causes of death in the developed countries. A majority of myocardial infarctions are caused by the rupture of coronary artery plaques. In order to achieve a better understanding of the effect of the extension of the lipid core into the artery wall on the change of flow field and its effect on plaque vulnerability, we have studied the hemodynamic parameters by utilizing a finite element method and taking into account the fluid-structure interaction (FSI). Four groups of stenosis models with different sizes of lipid core were used in the study. The fully developed pulsatile velocity profile of the right coronary artery was used as the inlet boundary condition, and the pressure pulse was applied as the outlet boundary condition. The non-Newtonian Carreau model was used to simulate the non-Newtonian behavior of blood. Results indicate that the extension of the lipid core into the artery wall influences the flow field; subsequently, creates favorable conditions for additional development of the lipid core which can lead to a higher risk of plaque rupture.

A numerical study on pulsatile non-Newtonian hemodynamics in double-fusiform abdominal aortic aneurysms

Abdominal Aortic Aneurysm (AAA) is a multi-factorial pathological event that occurs in the human body. In the present work, the hemodynamics pertaining to AAA are numerically analyzed. To comprehend the blood flow phenomenon in a double-fusiform aneurysm, axisymmetric simulations of pulsatile non-Newtonian blood flow are performed using OpenFOAM. The Carreau–Yasuda model is used to evaluate the non-Newtonian behavior of blood. The Reynolds number and Womersley number are altered as per the physiologically applicable range to characterize the hemodynamics. The Dilatation Index is also varied to quantify the consequence of different enlargements of the abdominal aorta on the blood flow. Four hemodynamic indicators—time-averaged wall shear stress, Oscillatory Shear Index (OSI), Relative Residence Time (RRT), and vascular impedance—are used to identify several complications such as atherosclerosis, vascular inflammation, endothelial dysfunction, and hyperplasia. As the pulse rate increases, the chances of particle stagnation inside the aneurysm decrease due to lower RRT. Our results suggest that patients with hypoxia or bradycardia (low Womersley number) are more susceptible to atherosclerosis due to the high value of RRT. Thus, we recommend mild exercise for patients with AAA. After analyzing the hemodynamic indicators, % of area with RRT &amp;gt; 0.5 is identified as the critical parameter to propose a regime map. Low pulse rates are found to be critical at low flow rates, whereas high pulse rates are found to be critical with high flow rates. Furthermore, it is found that the severity increases as the size of the aneurysm increases.

INVESTIGATION OF FLOW IN AN IDEALIZED CURVED ARTERY: COMPARATIVE STUDY USING CFD AND FSI WITH NEWTONIAN AND NON-NEWTONIAN FLUIDS

Artery curvatures, where disturbed flow patterns are expected, are preferred sites of formation of atherosclerosis. Experimental studies have shown that low and oscillating wall shear stress (WSS) plays an important role in the development and progression of atherosclerosis. Accurate estimation of these biomechanical parameters is important to assess the risk of atherosclerosis formation. The coupled effects of non-Newtonian behavior of blood and artery wall flexibility for the transient blood flow through an idealized curved coronary artery are investigated using computational fluid dynamics (CFD) as well as fluid–structure interaction (FSI) simulations. The choice of fluid model, Carreau and Newtonian, was found to impact the time averaged and minimum WSS values. The effects of wall deformation on time averaged wall shear tress were negligible. However, a comparison of temporal minima of WSS along the curvature showed significant variations between CFD and FSI simulations. Since low WSS values are crucial in the prediction of atherosclerosis development, it is concluded that both the non-Newtonian behavior of blood and the wall flexibility should be considered for computational studies.