Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Numerical Simulation Of Fluid Structure Interaction For Tilting Disk Mechanical Heart Valves
Download Numerical Simulation Of Fluid Structure Interaction For Tilting Disk Mechanical Heart Valves full books in PDF, epub, and Kindle. Read online Numerical Simulation Of Fluid Structure Interaction For Tilting Disk Mechanical Heart Valves ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Numerical Simulation of Fluid-structure Interaction for Tilting-disk Mechanical Heart Valves by : Ardavan Aliabadi
Download or read book Numerical Simulation of Fluid-structure Interaction for Tilting-disk Mechanical Heart Valves written by Ardavan Aliabadi and published by . This book was released on 2013 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: According to the United States Department of Health and Human Services, 27.1 million non-institutionalized adults were diagnosed with heart disease in 2010. The number of deaths associated with heart disease in 2009 was reported to be 599,413, claiming the lives of 195 out of every 100,000 people, which makes heart disease the number one killer in the U.S. Even though mechanical heart valves (MHVs) have proven to save lives in many of these cases, they are still not perfect, and complications arising from their design have reduced their application. To better understand the important factors and pursue remedies, numerous experimental investigations have been conducted; however, despite impressive improvements, small-scale studies suffer from lower levels of accuracy and sometimes are very costly to conduct. As in many other areas of research, numerical simulations can be helpful in reducing costs and supplementing such experimental work. The computational effort in this thesis focused on the numerical analysis of current tilting-disk MHVs. In this work, an implicit fluid-structure interaction (FSI) simulation of the Bjork-Shiley design was carried out using in-house codes implemented in the commercial code software FLUENT. In-house codes in the form of journal files, schemes, and user-defined functions (UDFs) were integrated to automate the inner iterations and enable communication between the fluid and the moving disk at the interfaces. Based on the investigation of the current simulations, a new design aiming at improving the hemodynamic performance is suggested. The hemodynamics of flow in current tilting-disk valves was compared with the suggested design, and it is concluded that the suggested design has a better hemodynamic performance in terms of shear stress values and residence times.
Book Synopsis Numerical Simulation of Pulsatile Blood Flow Across a Tilting-disk Mechanical Heart Valve by : Alireza Nejadmalayeri
Download or read book Numerical Simulation of Pulsatile Blood Flow Across a Tilting-disk Mechanical Heart Valve written by Alireza Nejadmalayeri and published by . This book was released on 2007 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: To overcome several clinical challenges involving mechanical heart valves, accurate numerical simulation of blood flow through these devices has been of interest. Since heart disease is the leading cause of death around the world, the hemodynamic study of the heart is of extraordinary interest in the field of bio fluid dynamics. Recent numerical/experimental investigations have shown that mechanical heart valves inherit the "production of sufficiently large shear and turbulent stresses to cause clinical problems such as hemolysis." Due to several parameters including the non-Newtonian behavior of blood, pulsatile waveform, strong blood and tissue interactions, clinical difficulties, etc., experimental examination of blood flow in the heart and its valves is a very difficult task. Therefore, comprehensive numerical analysis of this complex fluid-structure system is essential. However, precise experimental investigations are still imperative for developing appropriate and accurate turbulence models and for validating numerical techniques.In the current computational effort, the first set of objectives was numerical investigations of vortex shedding behind a two-dimensional tilting-disk mechanical heart valve in a straight channel, which is a simplified representation of the mitral position, using first- and several higher-order finite volume schemes as well as examination of the non-Newtonian viscosity effects on shedding frequency and amplitude.
Book Synopsis Modeling and Numerical Simulation of Fluid-Structure Interaction in Circle of Willis by : Aria Alimi
Download or read book Modeling and Numerical Simulation of Fluid-Structure Interaction in Circle of Willis written by Aria Alimi and published by kassel university press GmbH. This book was released on 2019-01-01 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main focus of this study is based on the numerical study of hemodynamics of blood and arterial wall behavior in Circle of Willis.
Book Synopsis A Fluid-structure Interaction Simulation of Mechanical Heart Valve Flow Dynamics by : Rui Cheng
Download or read book A Fluid-structure Interaction Simulation of Mechanical Heart Valve Flow Dynamics written by Rui Cheng and published by . This book was released on 2003 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Modeling of Large-displacement Fluid-structure Interaction by : Kyle Alexander Williston
Download or read book Numerical Modeling of Large-displacement Fluid-structure Interaction written by Kyle Alexander Williston and published by . This book was released on 2012 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The demand for artificial heart valve replacements is increasing as a result of birth defects, ageing and disease. Collaboration between engineers, biologists and mathematicians is necessary to handle problems related to biocompatibility and fluid dynamics. As a result of the increased demand for artificial heart valves, many new designs have been developed recently. A method to test those designs is to use mathematical modeling. This method has a relatively low-cost and can be used as a preliminary tool before expensive prototypes are created. This research analyzes the use of the numerical modeling software LS-DYNA for large-displacement fluid-structure interaction. It is a preliminary study aimed at the analysis of heart valve dynamics. In particular, a channel with flap model is created in LS-DYNA. The model's physics, convergence and ability to handle large deformations is investigated.
Book Synopsis Numerical Methods for Fluid-structure Interaction Problems with Valves by : Nuno Miguel Diniz dos Santos
Download or read book Numerical Methods for Fluid-structure Interaction Problems with Valves written by Nuno Miguel Diniz dos Santos and published by . This book was released on 2007 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is motivated by the modelling and the simulation of fluid-structure interaction phenomena in the vicinity of heart valves. On the one hand, the interaction of the vessel wall is dealt with an Arbitrary Lagrangian Eule- rian (ALE) formulation. On the other hand the interaction of the valves is treated with the help of Lagrange multipliers in a Fictitious Domains-like (FD) formulation. After a synthetic presentation of the several methods available for the fluid-structure interaction in blood flows, we describe a method that permits capture the dynamics of a valve immersed in an in- compressible fluid. The coupling algorithm is partitioned which allows the fluid and structure solvers to remain independent. In order to follow the ves- sel walls, the fluid mesh is mobile, but it remains none the less independent of the valve mesh. In this way we allow large displacements without the need to perform remeshing. We propose a strategy to manage contact between several immersed structures. The algorithm is completely independent of the structure solver and is well adapted to the partitioned fluid-structure coupling. Lastly we propose a semi-implicit coupling scheme allowing to mix, effectively, the ALE and FD formulations. The methods considered are followed with several numerical tests in 2D and 3D.
Book Synopsis Image-Based Computational Modeling of the Human Circulatory and Pulmonary Systems by : Krishnan B. Chandran
Download or read book Image-Based Computational Modeling of the Human Circulatory and Pulmonary Systems written by Krishnan B. Chandran and published by Springer Science & Business Media. This book was released on 2010-11-18 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: Image-Based Computational Modeling of the Human Circulatory and Pulmonary Systems provides an overview of the current modeling methods and applications enhancing interventional treatments and computer-aided surgery. A detailed description of the techniques behind image acquisition, processing and three-dimensional reconstruction are included. Techniques for the computational simulation of solid and fluid mechanics and structure interaction are also discussed, in addition to various cardiovascular and pulmonary applications. Engineers and researchers involved with image processing and computational modeling of human organ systems will find this a valuable reference.
Book Synopsis High-performance Computing Numerical Fluid-structure Interaction Framework for the Simulation of Aortic Valve Hemodynamics by : Barna E. M. Becsek
Download or read book High-performance Computing Numerical Fluid-structure Interaction Framework for the Simulation of Aortic Valve Hemodynamics written by Barna E. M. Becsek and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Simulations of the Micro Flow Field in the Hinge Region of Bileaflet Mechanical Heart Valves by : Helene Anne Simon
Download or read book Numerical Simulations of the Micro Flow Field in the Hinge Region of Bileaflet Mechanical Heart Valves written by Helene Anne Simon and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Native heart valves with limited functionality are commonly replaced by a bileaflet mechanical heart valve (BMHV). However, despite their widespread use, BMHVs still cause major complications, including hemolysis, platelet activation, and thromboembolic events. These complications are believed to be due to the non-physiologic hemodynamic stresses imposed on blood elements by the hinge flows. Three-dimensional characterization of the hinge flows is therefore crucial to ultimately design BMHVs with lower complication rates. This study aims at simulating the pulsatile 3D hinge flows of various BMHVs placed and estimating the thromboembolic potential associated with each hinge. The hinge and leaflet geometries of clinical BMHVs are reconstructed from micro-computed tomography scans. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Physiologic flow boundary conditions and leaflet motion are extracted from the Fluid-Structure-Interaction simulations of the BMHV bulk flow. The accuracy of the solver is assessed by comparing the results with experimental data. The numerical results are analyzed using a particle tracking approach coupled with existing blood damage models to relate the flow structures to the risk for blood damage.
Book Synopsis Numerical Analysis on Simplified 2D Model of Heart Valve by : Lee Xin Leong
Download or read book Numerical Analysis on Simplified 2D Model of Heart Valve written by Lee Xin Leong and published by LAP Lambert Academic Publishing. This book was released on 2012 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, the increasing numbers of heart diseases cases is very worrying although the medication technologies are always improving and moving forward.In this book, numerical modeling was used to study the effect of blood flow velocity and leaflet displacement by different shape of simplified 2D model of heart valve leaflets during cardiac cycle.Five different shapes of mitral valve leaflets and aortic valve leaflets were created and the simulation was performed by using ADINA-Fluid Structure Interaction (FSI). Ellipse shape of leaflets could be chosen as the most suitable shape among these five shapes in further study of heart valve simulati
Book Synopsis Fluid-structure Interaction Simulation of Bileaflet and Monoleaflet Mechanical Heart Valve Flow Dynamics by : Morteza Kimiaghalam
Download or read book Fluid-structure Interaction Simulation of Bileaflet and Monoleaflet Mechanical Heart Valve Flow Dynamics written by Morteza Kimiaghalam and published by . This book was released on 2013 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, opening and closing behavior of monoleaflet and bileaflet prosthetic heart valves was simulated using 2D and 3D Fluid Structure Interaction (FSI) models. The FSI models were based on the arbitrary Lagrangian-Eulerian (ALE) method for moving boundaries. Leaflet and diaphragm motions were described by means of user-defined functions following the experimental setup in a previous study. The hemodynamic performance of monoleaflet valves at the opening angle of 45, 60, 75, 80, and 85 was compared and results from this study demonstrated that the optimal opening angle should fall between 75 and 80. As the opening angle further increased, even though the calculated flow parameters continued to improve, the large angle could prevent the valve to close properly, which might lead to the failure of the heart valve. Furthermore, the hemodynamic performance of bileaflet and monoleaflet heart valves following the design of St. Jude bileaflet valve with 85 of opening angle and Bjork-Shiley monoleaflet valve with 75 of opening angle was compared. Results demonstrated that the flow in the monoleaflet valve design had a lower maximum velocity compared to the bileaflet design during both opening and closing phases which resulted in lower chance for flow to transition to turbulence. The mean pressure gradients across the monoleaflet and bileaflet valves were similar and resulted in an analogous EOA for these valves. According to the results of this study, the bileaflet valve had higher chance of developing cavitation bubbles during the valve closure because of higher pressure drops across the valve.
Book Synopsis Fluid-Structure Interaction by : Stefan Frei
Download or read book Fluid-Structure Interaction written by Stefan Frei and published by Walter de Gruyter GmbH & Co KG. This book was released on 2017-11-20 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph discusses modeling, adaptive discretisation techniques and the numerical solution of fluid structure interaction. An emphasis in part I lies on innovative discretisation and advanced interface resolution techniques. The second part covers the efficient and robust numerical solution of fluid-structure interaction. In part III, recent advances in the application fields vascular flows, binary-fluid-solid interaction, and coupling to fractures in the solid part are presented. Moreover each chapter provides a comprehensive overview in the respective topics including many references to concurring state-of-the art work. Contents Part I: Modeling and discretization On the implementation and benchmarking of an extended ALE method for FSI problems The locally adapted parametric finite element method for interface problems on triangular meshes An accurate Eulerian approach for fluid-structure interactions Part II: Solvers Numerical methods for unsteady thermal fluid structure interaction Recent development of robust monolithic fluid-structure interaction solvers A monolithic FSI solver applied to the FSI 1,2,3 benchmarks Part III: Applications Fluid-structure interaction for vascular flows: From supercomputers to laptops Binary-fluid–solid interaction based on the Navier–Stokes–Cahn–Hilliard Equations Coupling fluid-structure interaction with phase-field fracture: Algorithmic details
Book Synopsis On the Analysis of Moving Heart Valves by : Jan Baptist Adrianus Maria Horsten
Download or read book On the Analysis of Moving Heart Valves written by Jan Baptist Adrianus Maria Horsten and published by . This book was released on 1990 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Simulation of Physiological Flows by : Alejandro Roldán-Alzate
Download or read book Simulation of Physiological Flows written by Alejandro Roldán-Alzate and published by . This book was released on 2008 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Simulation of Coupled Fluid and Solid Motions in a Leaflet Type Artificial Heart Valve by : Xueyan Yun
Download or read book Numerical Simulation of Coupled Fluid and Solid Motions in a Leaflet Type Artificial Heart Valve written by Xueyan Yun and published by . This book was released on 2000 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Immersogeometric Fluid–structure Interaction Analysis of Bioprosthetic Heart Valves by : David Michael Kamensky
Download or read book Immersogeometric Fluid–structure Interaction Analysis of Bioprosthetic Heart Valves written by David Michael Kamensky and published by . This book was released on 2016 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this dissertation is to develop numerical methods for fluid–structure interaction (FSI) analysis that are suitable for modeling and simulating bioprosthetic heart valves (BHVs). BHVs are prosthetic replacements for the valves that regulate blood flow through the heart. BHVs reproduce natural hemodynamic conditions by mimicking the structure of native heart valves: they consist of thin flexible leaflets, passively driven by interaction with surrounding fluid. Current designs frequently require replacement 10–15 years after implantation. Computer simulation may help identify causes of and solutions to durability issues. Despite much previous research into computer simulation of heart valve FSI, inconvenience or inaccuracy of readily available numerical methods have prevented widespread incorporation of FSI into models of heart valve mechanics. Challenges associated with heart valve FSI simulation include large deformations of the region occupied by fluid, with changes of topology as the valve opens and closes, and low mass of the structure relative to the fluid, which necessitates careful treatment of fluid–structure coupling. The presence of large pressure gradients also requires special attention to the treatment of fluid mass conservation. Further, a useful numerical method for studying and improving designs of BHVs should be able to capture variations of valve geometry without requiring major effort to construct geometry-specific discretizations. To meet these challenges, I develop a new numerical approach, combining the immersed boundary concept of capturing fluid–structure interfaces on unfitted discretizations with recent developments in isogeometric analysis (IGA), which directly uses geometrical designs of engineered systems as discrete analysis meshes. In this work, I immerse an isogeometric structure discretization into an unfitted analysis mesh of the fluid subproblem. I refer to the immersion of design geometries into unfitted analysis meshes as immersogeometric analysis. To reliably couple unfitted discretizations of the fluid and structure subproblems, I introduce a new semi-implicit time integration procedure and analyze its stability and convergence in the context of linear model problems. I verify that this analysis extrapolates to the nonlinear setting through numerical experiments and explore the validity of my modeling assumptions by comparing computer simulations with observations from an in vitro experiment.
Book Synopsis Numerical Simulation of Mitral Valve Function by : K. D. Lau
Download or read book Numerical Simulation of Mitral Valve Function written by K. D. Lau and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the mammalian heart there are four heart valves (HV), of which the largest is the mitral valve (MV). Key components in the circulatory system, correct HV function is vital to cardiovascular health. A tethered and asymmetric structure, the MV regulates unidirectional flow between the left atrium and left ventricle. MVfunction is divided between systole/closure, where theMVis required to sustain a pressure load ~120 mmHg whilst minimising flow reversal, and diastole/opening in which the MV is required to rapidly transition from closed to open in order to maximise the transport of blood. Directly affecting the heart, dysfunction of the MV can affect either opening or closing through stenoses or prolapse/regurgitation respectively. Complementing experimental techniques, numerical simulation of theMVoffers additional insights into MV function as unmeasurable variables such as the stresses can be approximated. Due to the immersed nature of the HVs, numerical simulation of the MV requires an approach that is able to model both the large deformation of the MV and non-uniform haemodynamics pressure load resulting from the blood/HV contact. In this work the finite element solver LS-DYNA has been used as it addresses both issues. Using this framework, anatomically sized MV models have been used to characterise the current methodology of reported HV simulations, showing that the fluid-structure interaction (FSI) modelling of the blood/HV contact is essential in the simulation of MV dynamics. Application of this FSI method has been applied to surgical repair technique of the MV known as the edge-to-edge repair, showing that more invasive procedures result in greater stress concentrations but impaired the flow rates. Further advances in this model have been used to examine growth and remodelling effect of the MV tissue in both normal and dysfunctional states.
