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    Bending-torsional Stability and Vibrations of Beams Conveying Pulsating Flow in the Presence of Free Stream

    , Ph.D. Dissertation Sharif University of Technology Askarian, Abdolreza (Author) ; Haddadpour, Hassan (Supervisor) ; Dehghani Firouzabadi, Rohollah (Co-Advisor)
    In the current study, stability and nonlinear vibration of bending-torsional extensible beams conveying internal pulsatile and uniform external flow are studied. The internal and external fluid flows are assumed to be incompressible and frictionless. Applying the extensibility to the pipe along its length and using the nonlinear Euler-Bernoulli beam model and including some appropriate additional assumptions, the 3D nonlinear equations of motion of a cantilevered composite pipe is obtained. In order to derive the equations governing the fluid-structure interaction, the internal flow effect is modeled as a distributed load along the pipe which contains the inertia, Coriolis and centrifugal... 

    2D computational fluid dynamic modeling of human ventricle system based on fluid-solid interaction and pulsatile flow

    , Article Basic and Clinical Neuroscience ; Volume 4, Issue 1 , 2013 , Pages 64-75 ; 2008126X (ISSN) Masoumi, N ; Framanzad, F ; Zamanian, B ; Seddighi, A. S ; Moosavi, M. H ; Najarian, S ; Bastani, D ; Sharif University of Technology
    Many diseases are related to cerebrospinal fluid (CSF) hydrodynamics. Therefore, understanding the hydrodynamics of CSF flow and intracranial pressure is helpful for obtaining deeper knowledge of pathological processes and providing better treatments. Furthermore, engineering a reliable computational method is promising approach for fabricating in vitro models which is essential for inventing generic medicines. A Fluid-Solid Interaction (FSI)model was constructed to simulate CSF flow. An important problem in modeling the CSF flow is the diastolic back flow. In this article, using both rigid and flexible conditions for ventricular system allowed us to evaluate the effect of surrounding brain... 

    Mathematical modeling of CSF pulsatile hydrodynamics based on fluid-solid interaction

    , Article IEEE Transactions on Biomedical Engineering ; Volume 57, Issue 6 , 2010 , Pages 1255-1263 ; 00189294 (ISSN) Masoumi, N ; Bastani, D ; Najarian, S ; Ganji, F ; Farmanzad, F ; Seddighi, A. S ; Sharif University of Technology
    Intracranial pressure (ICP) is derived from cerebral blood pressure and cerebrospinal fluid (CSF) circulatory dynamics and can be affected in the course of many diseases. Computer analysis of the ICP time pattern plays a crucial role in the diagnosis and treatment of those diseases. This study proposes the application of Linninger et al.s [IEEE Trans. Biomed. Eng. , vol. 52, no. 4, pp. 557565, Apr. 2005] fluidsolid interaction model of CSF hydrodynamic in ventricular system based on our clinical data from a group of patients with brain parenchyma tumor. The clinical experiments include the arterial blood pressure (ABP), venous blood pressure, and ICP in the subarachnoid space (SAS). These... 

    Pulsatile blood flow in total cavopulmonary connection: a comparison between Y-shaped and T-shaped geometry

    , Article Medical and Biological Engineering and Computing ; Volume 55, Issue 2 , 2017 , Pages 213-224 ; 01400118 (ISSN) Rajabzadeh Oghaz, H ; Firoozabadi, B ; Saidi, M. S ; Monjezi, M ; Navabi Shirazi, M. A ; Malakan Rad, E ; Sharif University of Technology
    Springer Verlag  2017
    Single-ventricle anomaly is a hereditary heart disease that is characterized by anatomical malformations. The main consequence of this malformation is desaturated blood flow, which without proper treatment increases the risk of death. The classical treatment is based on a three-stage palliative procedure which should begin from the first few days of patient’s life. The final stage is known as Fontan procedure, in which inferior vena cava is directly connected to pulmonary arteries without going through the ventricle. This connection is called total cavopulmonary connection (TCPC). After surgery, the single ventricle supplies adequate and saturated systemic blood flow to the body; however,... 

    Bending-torsional instability of a viscoelastic cantilevered pipe conveying pulsating fluid with an inclined terminal nozzle

    , Article Journal of Mechanical Science and Technology ; Volume 32, Issue 7 , July , 2018 , Pages 2999-3008 ; 1738494X (ISSN) Askarian, A. R ; Abtahi, H ; Firouz Abadi, R. D ; Haddadpour, H ; Dowell, E. H ; Sharif University of Technology
    Korean Society of Mechanical Engineers  2018
    In the present study, dynamic stability of a viscoelastic cantilevered pipe conveying fluid which fluctuates harmonically about a mean flow velocity is considered; while the fluid flow is exhausted through an inclined end nozzle. The Euler-Bernoulli beam theory is used to model the pipe and fluid flow effects are modelled as a distributed load along the pipe which contains the inertia, Coriolis, centrifugal and induced pulsating fluid flow forces. Moreover, the end nozzle is modelled as a follower force which couples bending vibrations with torsional ones. The extended Hamilton's principle and the Galerkin method are used to derive the bending-torsional equations of motion. The coupled... 

    Effect of different geometries in simulation of 3D viscous flow in francis turbine runners

    , Article Scientia Iranica ; Volume 16, Issue 4 B , 2009 , Pages 363-369 ; 10263098 (ISSN) Firoozabadi, B ; Dadfar, R ; Pirali, A. P ; Ahmadi, G ; Sharif University of Technology
    Overall turbine analysis requires large CPU time and computer memory, even in the present days. As a result, choosing an appropriate computational domain accompanied by a suitable boundary condition can dramatically reduce the time cost of computations. This work compares different geometries for numerical investigation of the 3D flow in the runner of a Francis turbine, and presents an optimum geometry with least computational effort and desirable numerical accuracy. The numerical results are validated with a GAMM Francis Turbine runner, which was used as a test case (GAMM workshop on 3D computation of incompressible internal flows, 1989) in which the geometry and detailed best efficiency... 

    Personalised deposition maps for micro- and nanoparticles targeting an atherosclerotic plaque: attributions to the receptor-mediated adsorption on the inflamed endothelial cells

    , Article Biomechanics and Modeling in Mechanobiology ; Volume 18, Issue 3 , 2019 , Pages 813-828 ; 16177959 (ISSN) Shamloo, A ; Forouzandehmehr, M ; Sharif University of Technology
    Springer Verlag  2019
    Endothelial inflammation as a prominent precursor to atherosclerosis elicits a distinct pathological surface expression of particular vascular proteins. To exhibit a site-specific behaviour, micro- and nanoparticles, as carriers of therapeutics or imaging agents, can distinguish and use these proteins as targeted docking sites. Here, a computational patient-specific model capturing the exclusive luminal qualities has been developed to study the transport and adsorption of particles decorated with proper antibodies over an atherosclerotic plaque located in the LAD artery of the patient. Particles, in nano- and micron sizes, have been decorated with Sialyl Lewisx (sLex), P-selectin aptamer... 

    Computational investigation of stenosis in curvature of coronary artery within both dynamic and static models

    , Article Computer Methods and Programs in Biomedicine ; Volume 185 , 2020 Biglarian, M ; Momeni Larimi, M ; Hassanzadeh Afrouzi, H ; Moshfegh, A ; Toghraie, D ; Javadzadegan, A ; Rostami, S ; Sharif University of Technology
    Elsevier Ireland Ltd  2020
    Background and Objective: Blood flow variation during cardiac cycle is the main mechanism of atherosclerotic development which is dependent on. Methods: The present work mainly tends to investigate stenosis effect in dynamic curvature of coronary artery. This paper presents numerical investigations on wall shear stress profiles in three-dimensional pulsatile flow through curved stenotic coronary arteries for both static and dynamic model. In order to do so, three-dimensional models related to the curved arteries with two degrees of stenosis (30% and 50%). Results: Lower amount of wall shear stress is found near the inner wall of artery distal to the plaque region (stenosis) and in both... 

    The effect of hematocrit and nanoparticles diameter on hemodynamic parameters and drug delivery in abdominal aortic aneurysm with consideration of blood pulsatile flow

    , Article Computer Methods and Programs in Biomedicine ; Volume 195 , October , 2020 Jafarzadeh, S ; Nasiri Sadr, A ; Kaffash, E ; Goudarzi, S ; Golab, E ; Karimipour, A ; Sharif University of Technology
    Elsevier Ireland Ltd  2020
    Background and Objective: The present article has simulated to investigate the efficient hemodynamic parameters, the drug persistence, and drug distribution on an abdominal aortic aneurysm. Methods: Blood as a non-Newtonian fluid enters the artery acting as a real pulse waveform; its behavior is dependent on hematocrit and strain rate. In this simulation of computational fluid dynamic, magnetic nanoparticles of iron oxide which were in advance coated with the drug, are injected into the artery during a cardiac cycle. A two-phase model was applied to investigate the distribution of these carriers. Results: The results are presented for different hematocrits and the nanoparticle diameter. It... 

    Healthy and diseasedin vitromodels of vascular systems

    , Article Lab on a Chip ; Volume 21, Issue 4 , 2021 , Pages 641-659 ; 14730197 (ISSN) Hosseini, V ; Mallone, A ; Nasrollahi, F ; Ostrovidov, S ; Nasiri, R ; Mahmoodi, M ; Haghniaz, R ; Baidya, A ; Salek, M. M ; Darabi, M. A ; Orive, G ; Shamloo, A ; Dokmeci, M. R ; Ahadian, S ; Khademhosseini, A ; Sharif University of Technology
    Royal Society of Chemistry  2021
    Irregular hemodynamics affects the progression of various vascular diseases, such atherosclerosis or aneurysms. Despite the extensive hemodynamics studies on animal models, the inter-species differences between humans and animals hamper the translation of such findings. Recent advances in vascular tissue engineering and the suitability ofin vitromodels for interim analysis have increased the use ofin vitrohuman vascular tissue models. Although the effect of flow on endothelial cell (EC) pathophysiology and EC-flow interactions have been vastly studied in two-dimensional systems, they cannot be used to understand the effect of other micro- and macro-environmental parameters associated with... 

    Effects of pulsation on grid-generated turbulence

    , Article Journal of Fluids Engineering, Transactions of the ASME ; Volume 123, Issue 4 , 2001 , Pages 948-958 ; 00982202 (ISSN) Shahidinejad, S ; Jerphanion, I ; Magaud, F ; Souhar, M ; Sharif University of Technology
    The effects of low frequency, large amplitude sinusoidal pulsation on grid-generated turbulence (PGGT) were experimentally studied. Two-component hot wire anemometry technique was used. Pulsation did not change homogeneous, isotropic character of grid-generated turbulence. © 2001 by ASME