USING ATLAS OF HEART SHAPES FOR SIMULATION OF BLOOD FLOW IN LEFT VENTRICLE

2013 ◽  
Vol 25 (06) ◽  
pp. 1350050 ◽  
Author(s):  
Mir-Hossein Moosavi ◽  
Nasser Fatouraee ◽  
Hamid Katoozian ◽  
Ali Pashaei ◽  
Alejandro F. Frangi
Keyword(s):  
Blood Flow ◽  
Left Ventricle ◽  
Moving Boundary ◽  
Initial Conditions ◽  
Flow Characteristics ◽  
Computational Domain ◽  
Arbitrary Lagrangian Eulerian ◽  
Clinical Value ◽  
Aortic Sinus ◽  
Physiological Models

Integrative modeling of cardiac system is important for understanding the complex biophysical function of the heart]. To this end, multimodal cardiovascular imaging plays an important role in providing the computational domain, the boundary/initial conditions, and tissue function and properties. In particular, the incorporation of blood flow in the physiological models can help to simulate the hemodynamic properties and their effects on cardiac function. In this paper, we present a multimodal framework for quantitative and subject-specific analysis of blood flow in the cardiac chambers, including the left ventricle (LV). The 3D geometries of the LV at different time steps are extracted from medical images using an atlas of LV shape. The motion of the myocardium wall is used to extract the moving boundary data of the computational geometry. The data is used as a constraint for the computational fluid dynamics (CFD). An arbitrary Lagrangian–Eulerian (ALE) finite element method (FEM) formulation is used to derive a numerical solution of the transient dynamic equation of the fluid domain. With this method, simulation results describe detailed flow characteristics (such as velocity, pressure and wall shear stress) in the computational domain. The personalized hemodynamic characteristics obtained with the proposed approach can provide clinical value for diagnosis and treatment of abnormalities related to disturbed blood flow such as in myocardial remodeling and aortic sinus lesion formation.

Simulation of Passive Left Ventricle Filling

2009 ◽  
Author(s):  
Matthew G. Doyle ◽  
Stavros Tavoularis ◽  
Yves Bourgault
Keyword(s):  
Blood Flow ◽  
Stress State ◽  
Left Ventricle ◽  
Cardiac Cycle ◽  
Initial Conditions ◽  
Diastolic Pressure ◽  
Canine Heart ◽  
Structure Interaction ◽  
A Value ◽  
Starting Conditions

The overall objective of this research is to develop a model of the mechanics of the left ventricle (LV) of a canine heart, including blood flow, myocardium motion, and the interaction between the two. The focus of this part of the research is on calculating initial conditions for simulations of the cardiac cycle, by performing both solid-only and fluid-structure interaction (FSI) simulations of passive LV filling. Passive refers to the state at which the muscle fibers in the LV wall are fully relaxed. During these simulations, the LV is pressurized to a value of the end-diastolic pressure, which is within the physiological range. This allows us to use the resulting deformed geometry and stress state as starting conditions for cardiac cycle simulations.

Mach Number on Outlet Plane of a Straight Micro-Tube

2013 ◽  
Author(s):  
Y. Asako ◽  
D. Kawashima ◽  
T. Yamada ◽  
C. Hong
Keyword(s):  
Mach Number ◽  
Turbulent Flow ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Ideal Gas ◽  
Computational Domain ◽  
Arbitrary Lagrangian Eulerian ◽  
Downstream Region ◽  
Laminar And Turbulent Flow ◽  
Energy Equations

The Mach number and pressure on the outlet plane of a straight micro-tube were investigated numerically for both laminar and turbulent flow cases. The numerical methodology is based on the Arbitrary-Lagrangian-Eulerian (ALE) method. The LB1 turbulence model was used for the turbulent flow case. The compressible momentum and energy equations with the assumption of the ideal gas were solved. The computational domain is extended to the downstream region from the micro-tube outlet. The back pressure was given to the outside of the downstream region. The computations were performed for a tube whose diameter ranges from 50 to 500 μm. The average Mach number on the outlet plane of the fully under-expanded flow depends on the tube diameter and ranges from 1.16 to 1.25. The flow characteristics of the under-expanded gas flow in a straight micro-tube were revealed.

A Computer Simulation of the Blood Flow at the Aortic Bifurcation With Flexible Walls

1993 ◽  
Vol 115 (3) ◽  
pp. 306-315 ◽  
Author(s):  
Zheng Lou ◽  
Wen-Jei Yang
Keyword(s):  
Blood Flow ◽  
Moving Boundary ◽  
Shear Stresses ◽  
Arbitrary Lagrangian Eulerian ◽  
Aortic Bifurcation ◽  
Arbitrary Lagrangian Eulerian Method ◽  
Flexible Walls ◽  
Linear Viscoelastic ◽  
Flow Reversals

To understand the role of fluid dynamics in atherogenesis, especially the effect of the flexibility of arteries, a two-dimensional numerical model for blood flow at the aortic bifurcation with linear viscoelastic walls is developed. The arbitrary Lagrangian-Eulerian method is adopted to deal with the moving boundary problem. The wall expansion induces flow reversals or eddies during the decelerating systole while the wall contraction restricts them during the diastole. A flexible bifurcation experiences the shear stresses about 10 percent lower than those of a rigid one.

Wind-Structure Interaction by the Numerical Simulation

1999 ◽  
Vol 15 (1) ◽  
pp. 35-39
Author(s):  
D. L. Young ◽  
J. T. Chang
Keyword(s):  
External Field ◽  
Moving Boundary ◽  
Stokes Equations ◽  
Numerical Code ◽  
Computational Domain ◽  
Arbitrary Lagrangian Eulerian ◽  
Number Range ◽  
Explicit Finite Element ◽  
Structure Interaction ◽  
Wind Structure

ABSTRACTA new computational procedure is developed to solve the external field problems of the incompressible viscous flows. The method is able to solve the infinite boundary value problems by extracting the boundary effects coming from the finite computational domain. The present method is based on the projection method of the Navier-Stokes equations. We use three-step explicit finite element method to solve the momentum equation of the flow motion. The external field solver of the boundary element is used to treat the pressure Poisson equation. The arbitrary Lagrangian-Eulerian method is employed to deal with the moving boundary, such as wind-structure interaction problems. For illustration of the present numerical code, a vortex-induced cross-flow oscillations of a circular cylinder mounted on an elastic dashpot-spring system is considered. The phenomena of the beat, lock-in, and resonance are revealed in the Reynolds number range between 100 and 110, which are much narrower than the previous studies.

Study of a Crossflow over a Zero-Net-Mass-Flux Synthetic Jet Driven by a Vibrating Diaphragm

2011 ◽  
Vol 27 (4) ◽  
pp. 503-509 ◽  
Author(s):  
L.-Y. Tseng ◽  
A.-S. Yang ◽  
J.-C. Lin
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Turbulent Flows ◽  
Mass Flux ◽  
Moving Boundary ◽  
Active Flow Control ◽  
Flow Characteristics ◽  
Synthetic Jet ◽  
Computational Domain ◽  
Zero Net Mass Flux

ABSTRACTMiniature synthetic jet actuators are low operating power, zero-net-mass-flux and very compact devices which have demonstrated their capability in modifying the subsonic flow characteristics for boundary layer flow control. In order to improve the design active flow control systems, the present study aims to examine the formation and interaction of unsteady flowfield of a synthetic jet with external crossflow. In view of a single synthetic jet emitting into a turbulent boundary layer crossflow via a circular orifice, the theoretical model utilized the transient three-dimensional conservation equations of mass and momentum for compressible, turbulent flows with a negligible temperature variation over the computational domain. The motion of a movable membrane plate was also treated as the moving boundary by prescribing the displacement on the plate surface. The predictions by the computational fluid dynamics (CFD) software ACE+®were compared with the measured transient phase-averaged velocities in literature for code validation. The predictions showed the time evolution of the large vortical structure originating from the jet orifice and its successive interaction with the crossflow to change the flow structure inside the boundary layer.

Mach number at outlet plane of a straight micro-tube

2016 ◽  
Vol 230 (19) ◽  
pp. 3420-3430 ◽  
Author(s):  
D Kawashima ◽  
T Yamada ◽  
C Hong ◽  
Y Asako
Keyword(s):  
Mach Number ◽  
Turbulent Flow ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Ideal Gas ◽  
Computational Domain ◽  
Arbitrary Lagrangian Eulerian ◽  
Choked Flow ◽  
Downstream Region ◽  
Energy Equations

The Mach number and pressure at the outlet plane of a straight micro-tube were investigated numerically for both laminar and turbulent flow cases. The numerical methodology is based on the arbitrary Lagrangian-Eulerian method. The LB1 turbulence model was used for the turbulent flow case. The compressible momentum and energy equations with the assumption of the ideal gas were solved. The computational domain is extended to the downstream region from the micro-tube outlet. The back pressure was given to the outside of the downstream region. The computations were performed for a tube whose diameter ranges from 50 to 500 μm. The average Mach number at the outlet plane of the choked flow depends on the tube diameter and ranges from 1.16 to 1.25. The flow characteristics of the under-expanded gas flow in a straight micro-tube were revealed.

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