Simulation of one‐dimensional blood flow in networks of human vessels using a novel TVD scheme

A 1-dimensional (1D)-3-dimensional (3D) multiscale model for the human vascular network was proposed by combining a low-fidelity 1D modeling of blood circulation to account for the global hemodynamics with a detailed 3D simulation of a zonal vascular segment. The coupling approach involves a direct exchange of flow and pressure information at interfaces between the 1D and 3D models and thus enables patient-specific morphological models to be inserted into flow network with minimum computational efforts. The proposed method was validated with good agreements against 3 simplified test cases where experimental data and/or full 3D numerical solution were available. The application of the method in aneurysm and stenosis studies indicated that the deformation of the geometry caused by the diseases may change local pressure loss and as a consequence lead to an alteration of flow rate to the vessel segment.

“…The 1D governing equations for blood flow in a vessel can be expressed as:

\frac{\partial A}{\partial t} + \frac{\partial q}{\partial x} = 0,

\frac{\partial q}{\partial t} + \frac{\partial}{\partial x} ((), α \frac{q^{2}}{A}) + \frac{A}{ρ} \frac{\partial P}{\partial x} = - f / ρ,

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

P_{ch} ((), t) = P_{e} + ((), E_{A} e ((), t) + E_{B}) ((), V_{ch} - V_{italicch, 0}) + S \frac{{italicdV}_{italicch}}{dt},

where E A and E B are the active and passive elastance respectively and V ch and V ch , 0 represent the chamber volume and dead chamber volume respectively.…”

Section: Methodsmentioning

confidence: 99%

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A multiscale computational modeling for cerebral blood flow with aneurysms and/or stenoses

Huang

Yang

et al. 2018

“…Its ability to redistribute blood depends highly on its morphology, as well as the presence and the shape of the communicating arteries. The effect of anatomical variation of the CoW on CVDs has been thoroughly studied . A close correlation between low distribution capacity of the CoW and an increased risk of stroke has been reported .…”

Section: Introductionmentioning

confidence: 99%

Quantification of near‐wall hemodynamic risk factors in large‐scale cerebral arterial trees

Ghaffari

Alaraj

et al. 2018

Detailed hemodynamic analysis of blood flow in pathological segments close to aneurysm and stenosis has provided physicians with invaluable information about the local flow patterns leading to vascular disease. However, these diseases have both local and global effects on the circulation of the blood within the cerebral tree. The aim of this paper is to demonstrate the importance of extending subject-specific hemodynamic simulations to the entire cerebral arterial tree with hundreds of bifurcations and vessels, as well as evaluate hemodynamic risk factors and waveform shape characteristics throughout the cerebral arterial trees. Angioarchitecture and in vivo blood flow measurement were acquired from healthy subjects and in cases with symptomatic intracranial aneurysm and stenosis. A global map of cerebral arterial blood flow distribution revealed regions of low to high hemodynamic risk that may significantly contribute to the development of intracranial aneurysms or atherosclerosis. Comparison of pre-intervention and post-intervention of pathological cases further shows large angular phase shift (~33.8°), and an augmentation of the peak-diastolic velocity. Hemodynamic indexes of waveform analysis revealed on average a 16.35% reduction in the pulsatility index after treatment from lesion site to downstream distal vessels. The lesion regions not only affect blood flow streamlines of the proximal sites but also generate pulse wave shift and disturbed flow in downstream vessels. This network effect necessitates the use of large-scale simulation to visualize both local and global effects of pathological lesions.

“…Although the lumped model is useful to study experimental measurements and simple scenarios, it is not a robust model for predicting temperature distribution in space and time. A more robust model may be constructed using a 1‐dimensional tree with fluid‐structure interaction models similar to blood flow analysis . Such a model is very useful when local flow distribution is of interest.…”

Section: Introductionmentioning

confidence: 99%

A novel modelling approach to energy transport in a respiratory system

Nithiarasu

Sazonov

2017

In this paper, energy transport in a respiratory tract is modelled using the finite element method for the first time. The upper and lower respiratory tracts are approximated as a 1-dimensional domain with varying cross-sectional and surface areas, and the radial heat conduction in the tissue is approximated using the 1-dimensional cylindrical coordinate system. The governing equations are solved using 1-dimensional linear finite elements with convective and evaporative boundary conditions on the wall. The results obtained for the exhalation temperature of the respiratory system have been compared with the available animal experiments. The study of a full breathing cycle indicates that evaporation is the main mode of heat transfer, and convection plays almost negligible role in the energy transport. This is in-line with the results obtained from animal experiments.