Wall orientation and shear stress in the lattice Boltzmann model

Matyka, Maciej; Koza, Zbigniew; Mirosław, Łukasz

doi:10.1016/j.compfluid.2012.12.018

Cited by 37 publications

(22 citation statements)

References 47 publications

(51 reference statements)

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“…Although the grid-based normal n j is appropriate for extrapolating S αβ from the computational nodes to the boundary points, the normal used to find the components in equation (18) was based on the local wall geometry as N j · B j = 0, where B j = b j+10 − b j−10 is a measure of the local surface. The value of 10 was selected to give a smooth measure of the surface, and is comparable to the value used in [41]. Figure 9 shows the Peak WSS (PWSS) on the stenosed regions of the outer ECA and ICA walls.…”

Section: Resultsmentioning

confidence: 99%

An LBM based model for initial stenosis development in the carotid artery

Στάμου¹,

Buick²

2016

J. Phys. A: Math. Theor.

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A numerical scheme is proposed to simulate the early stages of stenosis development based on the properties of blood flow in the carotid artery, computed using the lattice Boltzmann method. The model is developed on the premise, supported by evidence from the literature, that the stenosis develops in regions of low velocity and low wall shear stress. The model is based on two spatial parameters which relate to the extent to which the stenosis can grow in each development phase. Simulations of stenosis development are presented for a range of the spacial parameters to determine suitable ranges for their application. Flow fields are also presented which indicate that the stenosis is developing in a realistic manner, providing evidence that stenosis development is indeed influenced by the low shear stress, rather than occurring in such areas coincidentally.

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Section: Resultsmentioning

confidence: 99%

An LBM based model for initial stenosis development in the carotid artery

Στάμου¹,

Buick²

2016

J. Phys. A: Math. Theor.

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“…[34][35][36] When simulating systolic blood flow in the abdominal aorta and mesenteric artery using both FEM and LBM, it was found that the LBM is as accurate as FEM for solving complex blood flows. 38,39 Therefore, using the LBM is appropriate for high resolution 3D simulations. 36 LBM was found to have improved cost per time step, code implementation, and parallelization.…”

Section: Discussionmentioning

confidence: 99%

“…37 Chapman-Enskog analysis furthermore showed that LBM reproduces the incompressible Navier-Stokes equations. 38,39 Therefore, using the LBM is appropriate for high resolution 3D simulations.…”

Section: Discussionmentioning

confidence: 99%

Impact of diversity of morphological characteristics and Reynolds number on local hemodynamics in basilar aneurysms

et al. 2018

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Morphological and hemodynamic parameters have been suggested to affect the rupture of cerebral aneurysms, but detailed mechanisms of rupture are poorly understood. The purpose of our study is to determine criteria for predicting the risk of aneurysm rupture, which is critical for improved patient management. Existing aneurysm hemodynamics studies generally evaluate limited geometries or Reynolds numbers (Re), which are difficult to apply to a wide range of patient‐specific cases. Association between hemodynamic characteristics and morphology is focused. Several two‐dimensional (2D) and three‐dimensional (3D) idealized and physiological geometries is assessed to characterize the hemodynamic landscape between flow patterns. The impact of morphology on velocity and wall shear stress (WSS) profiles were evaluated. Slight changes in aneurysm geometry is found or Re result in significant changes in the hemodynamic and WSS profiles. Our systematic mapping and nondimensional analysis qualitatively identify hemodynamic conditions that may predispose aneurysms to rupture. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2792–2802, 2018

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“…An in-house developed massively parallel CFD code, HARVEY, was used to simulate hemodynamics in the 3 computational models. 19,25,24,32 The hemodynamics solver HARVEY uses an implementation of the lattice Boltzmann method (LBM) to solve the Navier-Stokes equations governing fluid flows in complex 3D geometries. 3,17,36 Discretizing space and velocity with a fixed Cartesian lattice, LBM models the fluid with a particle distribution function , which denotes the probability of finding a particle at time t and lattice point with the discrete velocity .…”

Section: Cfd Simulations Using Harveymentioning

confidence: 99%

“…To compute the WSS vector , the stress tensor σ αβ is computed from the nonequilibrium distribution: . Using the approach from Matyka et al, 19 the outward nor- mal vector is estimated, and the WSS vector components are computed as . Additional details about the HARVEY implementation, parallelization, and scaling may be found in the articles by Randles et al 24,25 TAWSS and OSI are defined as: 21 where represents the instantaneous WSS vector and T is the period of the cardiac cycle.…”

Section: Cfd Simulations Using Harveymentioning

confidence: 99%

Hemodynamic and morphological characteristics of a growing cerebral aneurysm

Dabagh¹,

Nair²,

Gounley³

et al. 2019

Neurosurgical Focus

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The growth of cerebral aneurysms is linked to local hemodynamic conditions, but the driving mechanisms of the growth are poorly understood. The goal of this study was to examine the association between intraaneurysmal hemodynamic features and areas of aneurysm growth, to present the key hemodynamic parameters essential for an accurate prediction of the growth, and to gain a deeper understanding of the underlying mechanisms. Patient-specific images of a growing cerebral aneurysm in 3 different growth stages acquired over a period of 40 months were segmented and reconstructed. A unique aspect of this patient-specific case study was that while one side of the aneurysm stayed stable, the other side continued to grow. This unique case enabled the authors to examine their aims in the same patient with parent and daughter arteries under the same inlet flow conditions. Pulsatile flow in the aneurysm models was simulated using computational fluid dynamics and was validated with in vitro experiments using particle image velocimetry measurements. The authors’ detailed analysis of intrasaccular hemodynamics linked the growing regions of aneurysms to flow instabilities and complex vortex structures. Extremely low velocities were observed at or around the center of the unstable vortex structure, which matched well with the growing regions of the studied cerebral aneurysm. Furthermore, the authors observed that the aneurysm wall regions with a growth greater than 0.5 mm coincided with wall regions of lower (< 0.5 Pa) time-averaged wall shear stress (TAWSS), lower instantaneous (< 0.5 Pa) wall shear stress (WSS), and high (> 0.1) oscillatory shear index (OSI). To determine which set of parameters can best identify growing and nongrowing aneurysms, the authors performed statistical analysis for consecutive stages of the growing CA. The results demonstrated that the combination of TAWSS and the distance from the center of the vortical structure has the highest sensitivity and positive predictive value, and relatively high specificity and negative predictive value. These findings suggest that an unstable, recirculating flow structure within the aneurysm sac created in the region adjacent to the aneurysm wall with low TAWSS may be introduced as an accurate criterion to explain the hemodynamic conditions predisposing the aneurysm to growth. The authors’ findings are based on one patient’s data set, but the study lays out the justification for future large-scale verification. The authors’ findings can assist clinicians in differentiating stable and growing aneurysms during preinterventional planning.

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Wall orientation and shear stress in the lattice Boltzmann model

Cited by 37 publications

References 47 publications

An LBM based model for initial stenosis development in the carotid artery

An LBM based model for initial stenosis development in the carotid artery

Impact of diversity of morphological characteristics and Reynolds number on local hemodynamics in basilar aneurysms

Hemodynamic and morphological characteristics of a growing cerebral aneurysm

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