Quasi-Two-Dimensional Numerical Analysis of Fast Transient Flows Considering Non-Newtonian Effects

Tazraei, Pedram; Riasi, Alireza

doi:10.1115/1.4031093

Cited by 26 publications

(3 citation statements)

References 24 publications

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“…Moreover, blood viscosity has been assumed to be constant in most published papers by using the dynamic viscosity of μ = 0.0035 Pa.s, but in some papers blood has been assumed to be a non-Newtonian fluid by utilizing the Carreau–Yasuda model [ 36 ] and the Carreau [ 34 ] model. In many publications [ 45 – 51 ], it has been shown that blood significantly possesses the non-Newtonian properties, such as shear thinning, viscoelasticity, and thixotropic. In our most recent publications [ 18 , 52 ], the effect of the non-Newtown assumption on the flow dynamics was analyzed by using different blood rheological models under the physiological condition.…”

Section: Computational Fluid Dynamics (Cfd) Approachesmentioning

confidence: 99%

Heart blood flow simulation: a perspective review

Doost

Ghista²,

et al. 2016

BioMed Eng OnLine

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Cardiovascular disease (CVD), the leading cause of death today, incorporates a wide range of cardiovascular system malfunctions that affect heart functionality. It is believed that the hemodynamic loads exerted on the cardiovascular system, the left ventricle (LV) in particular, are the leading cause of CVD initiation and propagation. Moreover, it is believed that the diagnosis and prognosis of CVD at an early stage could reduce its high mortality and morbidity rate. Therefore, a set of robust clinical cardiovascular assessment tools has been introduced to compute the cardiovascular hemodynamics in order to provide useful insights to physicians to recognize indicators leading to CVD and also to aid the diagnosis of CVD. Recently, a combination of computational fluid dynamics (CFD) and different medical imaging tools, image-based CFD (IB-CFD), has been widely employed for cardiovascular functional assessment by providing reliable hemodynamic parameters. Even though the capability of CFD to provide reliable flow dynamics in general fluid mechanics problems has been widely demonstrated for many years, up to now, the clinical implications of the IB-CFD patient-specific LVs have not been applicable due to its limitations and complications. In this paper, we review investigations conducted to numerically simulate patient-specific human LV over the past 15 years using IB-CFD methods. Firstly, we divide different studies according to the different LV types (physiological and different pathological conditions) that have been chosen to reconstruct the geometry, and then discuss their contributions, methodologies, limitations, and findings. In this regard, we have studied CFD simulations of intraventricular flows and related cardiology insights, for (i) Physiological patient-specific LV models, (ii) Pathological heart patient-specific models, including myocardial infarction, dilated cardiomyopathy, hypertrophic cardiomyopathy and hypoplastic left heart syndrome. Finally, we discuss the current stage of the IB-CFD LV simulations in order to mimic realistic hemodynamics of patient-specific LVs. We can conclude that heart flow simulation is on the right track for developing into a useful clinical tool for heart function assessment, by (i) incorporating most of heart structures’ (such as heart valves) operations, and (ii) providing useful diagnostic indices based hemodynamic parameters, for routine adoption in clinical usage.

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Section: Computational Fluid Dynamics (Cfd) Approachesmentioning

confidence: 99%

Heart blood flow simulation: a perspective review

Doost

Ghista²,

et al. 2016

BioMed Eng OnLine

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“…Non-Newtonian constitutive equations can be divided into Generalized Newtonian Fluid (GNF) models and linear and nonlinear viscoelastic models. GNF non-Newtonian constitutive equations that can model non-elastic variable viscosity and viscoplastic fluids have a substantial contribution in the non-Newtonian fluid hammer research papers [13][14][15][16]. Oliveira et al [17] constructed a one-dimensional mathematical model to simulate viscoplastic fluid hammer, and they showed viscoplastic fluids produce smaller overpressure compared with Newtonian fluids.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of laminar viscoelastic fluid hammer phenomenon in an axisymmetric pipe

Badami

Riasi

Sadeghy

2021

J Braz. Soc. Mech. Sci. Eng.

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The aim of this study is to investigate the laminar fluid hammer phenomenon in viscoelastic fluids through a straight pipe. To pursue this aim, the finite-volume method is adopted to numerically assess the influences of the viscoelastic non-dimensional parameters on the viscoelastic fluid hammer in an axisymmetric pipe. Herein, the Phan-Thien-Tanner model is selected as the constitutive equation, which could be used to study the viscosity ratio, Deborah number, and the extensibility parameter simultaneously. The results are in good agreement with the experimental data and analytical solution. The impacts of the viscosity ratio, the Deborah number, and the extensibility parameter in constant Reynolds number on the pressure history, velocity profile, and wall shear stress history are investigated. Present results reveal that increasing viscosity ratio and decreasing the Deborah number lead to a shorter attenuation time; however, the viscosity ratio has a more profound effect compared with the Deborah number. The extensibility parameter has not any impact on the viscoelastic fluid hammer virtually. Moreover, lower viscosity ratios create stronger reversed flows. Finally, although increasing the viscosity ratio and decreasing the Deborah number provide a larger damping ratio in the wall shear stress history, these create larger wall shear stress in the earlier peaks.

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“…In recent years, various fast transient flow problems have been dealt with in the literature ranging from incidences encountered in industrial settings [5][6][7] to biologically issues such as the blood hammer [8][9]. The common denominator of all these problems is the existence of a disturbing factor within the system.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of the hydraulic transient response in the presence of surge tanks and relief valves

Riasi

Tazraei

2017

Renewable Energy

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Water hammer as a critical consequence of unsteadiness may take place in the penstock of the hydroelectric power plants. Hence, the unsteady flow analysis is important to identify undesirable pressure variations and to take preventive actions toward guaranteeing safe operation of the power plant. Chief among these actions are the installation of a surge tank and relief valve, and the transient flow behavior in the presence of protective devices is investigated herein. The method of characteristics is employed to numerically solve the equations governing the transient flow through channels. Also, in order to better resolve the transient behavior, unsteady friction effects have been considered. Validation of the developed computational code is carried out through comparison of the computed transient pressures with those measured at Karun-III Hydropower Plant. According to the results obtained for MONJ Hydropower Station, when only one turbine is in operation, the surge tank decreases the pressure rise within the spiral case and the turbine overspeed by 22% and 6%, respectively. While the percentages associated with employing a proper surge relief valves are accordingly 12% and 14%. This study substantiates how surge relief valves can be used instead of an expensive surge tank to relieve the transient response.

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Quasi-Two-Dimensional Numerical Analysis of Fast Transient Flows Considering Non-Newtonian Effects

Cited by 26 publications

References 24 publications

Heart blood flow simulation: a perspective review

Heart blood flow simulation: a perspective review

Numerical analysis of laminar viscoelastic fluid hammer phenomenon in an axisymmetric pipe

Numerical analysis of the hydraulic transient response in the presence of surge tanks and relief valves

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