Unsteady and Three-Dimensional Flow Simulations in the Human Aorta

Shahcheraghi, N.; Dwyer, H. A.; Cheer, A. Y.; Rutaganira, T.; Barakat, Abdul I.

doi:10.1007/978-3-642-56535-9_33

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…32,46 Hence, in this study, the distributions of HPs, including time-averaged WSS (TAWSS), nondimensional TAWSSG, 8 and OSI 26 are calculated according to their expressions in Eqs. (5) to (7), respectively, and compared in the three models.…”

Section: Hemodynamic Parameters Distributionmentioning

confidence: 99%

A Novel Coronary Artery Bypass Graft Design of Sequential Anastomoses

et al. 2010

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In this paper, the hemodynamics in a three-dimensional out-of-plane sequential bypass graft model is first investigated. Based on the advantageous flow characteristics observed within the side-to-side (STS) anastomosis in the sequential bypass graft simulation, a new CABG coupled-sequential anastomosis configuration is designed, entailing coupled STS and end-to-side (ETS) anastomotic components. In this new CABG design, the flow fields and distributions of various wall shear stress parameters within the STS and ETS anastomotic regions are studied, and compared to those of the conventional distal anastomosis, by means of computational fluid dynamics simulation of pulsatile Newtonian blood flow. Simulation results demonstrate that the new sequential anastomoses model provides: (i) a more uniform and smooth flow at the ETS anastomosis, without any stagnation point on the artery bed and vortex formation in the heel region of the ETS anastomosis within the coronary artery; (ii) a spare route for the blood flow to the coronary artery, to avoid re-operation in case of re-stenosis in either of the anastomoses; and (iii) improved distribution of hemodynamic parameters at the coronary artery bed and in the heel region of the ETS anastomosis, with more moderate shear stress indices. These advantages of the new design over the conventional ETS anastomosis are influenced by the occlusion ratio of the native coronary artery, and are most prominent when the proximal segment of the coronary artery is fully occluded. By varying the design parameters of the anastomotic angle and distance between the two anastomoses, the superior coupled STS-ETS anastomoses design is found to have the anastomotic angle of 30° and 30 mm distance between the two (STS and ETS) components.

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Section: Hemodynamic Parameters Distributionmentioning

confidence: 99%

A Novel Coronary Artery Bypass Graft Design of Sequential Anastomoses

et al. 2010

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“…6,8,25,31,36 Extensive clinical and computational studies have been performed to investigate fluid dynamics in bifurcations and curved arteries. Van de Vosse et al, 37 Perktold et al, 27 Gijsen et al, 11 and Shahcheraghi et al 30 presented numerical simulations of blood flow in curved tubes. Wall hemodynamic indicators such as wall pressure (WP), wall shear stress (WSS), and their spatial gradients (WPG and WSSG) have been investigated in curved arteries and a relationship between the predisposed sites of atherosclerosis formation and the regions of low WSS and WP or intense WPG and WSSG are proposed.…”

Section: Introductionmentioning

confidence: 98%

Bend Sweep Angle and Reynolds Number Effects on Hemodynamics of S-Shaped Arteries

Niazmand

Jaghargh

2010

Ann Biomed Eng

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The purpose of this study is to investigate the effects of the Reynolds number and the bend sweep angle on the blood flow patterns of S-shaped bends. The numerical simulations of steady flows in S-shaped bends with sweep angles of 45 degrees , 90 degrees , and 135 degrees are performed at Reynolds numbers of 125, 500, and 960. Hemodynamic characteristics such as secondary flows, vorticity, and axial velocity profiles are analyzed in detail. Flow patterns in S-shaped bends are strongly dependent on both Reynolds number and bend sweep angle, which can be categorized into three groups based on the first bend secondary flow effects on the transverse flow of the second bend. For low Reynolds numbers and any sweep angles, secondary flows in the second bend eliminate the first bend effects in the early sections of the second bend and therefore the axial velocity profile is consistent with the bend curvature, while for high Reynolds numbers depending on the bend sweep angles the secondary vortex pattern of the first bend may persist partially or totally throughout the second bend leading to a four-vortex secondary structure. Moreover, an interesting flow feature observed at the Reynolds number of 960 is that the secondary flow asymmetrical behavior occurred around the second bend exit and along the outflow straight section. This symmetry-breaking phenomenon which has not been reported in the previous studies is shown to be more pronounced in the 90 degrees S-shaped bend as compared to other models considered here. The probability of flow separation as one of the important flow features contributing to the onset and development of arterial wall diseases is also studied. It is observed that the second bend outer wall of gentle bends with sweep angles from 20 degrees to 30 degrees at high enough Reynolds numbers are prone to flow separation.

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Unsteady and Three-Dimensional Flow Simulations in the Human Aorta

Cited by 2 publications

References 4 publications

A Novel Coronary Artery Bypass Graft Design of Sequential Anastomoses

A Novel Coronary Artery Bypass Graft Design of Sequential Anastomoses

Bend Sweep Angle and Reynolds Number Effects on Hemodynamics of S-Shaped Arteries

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