Unsteady velocity measurements in a realistic intracranial aneurysm model

Ugron, Ádám; Farinas, Marie-Isabelle; Kiss, László I.; Paál, György

doi:10.1007/s00348-011-1206-z

Cited by 23 publications

(19 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The layout of the vessel section used during the current work was obtained from CT (X-ray computed tomography) angiography [41]. The flow field of the blood was obtained from an experimentally validated CFD (computational fluid dynamics) simulation [28] that used the lattice Boltzmann method [42] with a very fine numerical grid in order to handle the aforementioned highly curved and irregular nature of the geometry.…”

Section: Flow Fieldmentioning

confidence: 99%

“…This function is the same as the one used in Refs. [28] and [41]. The third, smaller outlet was defined as a constant pressure boundary to avoid over-constraining the model.…”

Section: Flow Fieldmentioning

confidence: 99%

“…The physical time-span of a simulated cardiac cycle was exactly 1 s. During this time, 36 snapshots of the flow field were recorded at equal time-steps to be used later for the tracer path integration. For a more detailed description of the simulation parameters and the boundary conditions see [28], where the validation of the flow field results against experimental data [41] are also described. Once the flow field v(r, t) is generated, it can be used to compute the path of passively advected particles fromṙ(t) = v(r, t) numerically, as discussed in Subsection 2.3.…”

Section: Flow Fieldmentioning

confidence: 99%

See 2 more Smart Citations

Emerging fractal patterns in a real 3D cerebral aneurysm

Závodszky¹,

Károlyi

Paál³

2015

Journal of Theoretical Biology

Self Cite

View full text Add to dashboard Cite

The behaviour of biological fluid flows is often investigated in medical practice to draw conclusions on the physiological or pathological conditions of the considered organs. One area where such investigations are proven to be useful is the flow-related formation and growth of different pathologic malformations of the cerebro vascular system. In this work, a detailed study is presented on the effect of a cerebral aneurysm on blood transport inside a human brain artery segment. This malformation causes strong flow instabilities that drives the flow system towards chaotic behaviour. The emerging fractal structure and some of its measurable properties have been explored using a method that makes the measurement of these properties feasible even in complicated large three dimensional data sets. We find that, from the investigated chaos parameters, the information dimension turns out to be the most reliable parameter to characterize chaotic advection in the vicinity of the aneurysm sac. We propose that properties of chaotic mixing close to aneurysms might be relevant for the condition of this pathologic malformation.

show abstract

Section: Flow Fieldmentioning

confidence: 99%

“…This function is the same as the one used in Refs. [28] and [41]. The third, smaller outlet was defined as a constant pressure boundary to avoid over-constraining the model.…”

Section: Flow Fieldmentioning

confidence: 99%

Section: Flow Fieldmentioning

confidence: 99%

See 1 more Smart Citation

Emerging fractal patterns in a real 3D cerebral aneurysm

Závodszky¹,

Károlyi

Paál³

2015

Journal of Theoretical Biology

Self Cite

View full text Add to dashboard Cite

show abstract

“…During the last decade, several PIV measurements have been performed on IA models to evaluate, on one hand, the influence of different geometry parameters on flow dynamics (Liou and Liao 1997;Yu and Zhao 1999;Tateshima et al 2003Tateshima et al , 2007Tateshima et al , 2008Liou et al 2007;Ford et al 2008a;Yamaguchi et al 2008;Morino et al 2010;Tanoue et al 2011;Raschi et al 2012), and on the other hand, to validate computational fluid dynamics (CFD) predictions (Hoi et al 2006;Ford et al 2008b;Mulder et al 2009;Ugron et al 2012;Le et al 2013). Idealized IA models, made of a spherical aneurysm connected to a cylindrical pipe, were essentially used to study the influence of several factors: (a) the curvature of the parent artery (Liou and Liao 1997), (b) the angular orientation of IA with respect to parent vessel (in basilar tip (Ford et al 2008a) and sidewall IAs (Liou et al 2007)) and (c) IA aspect ratio (Yamaguchi et al 2008) (i.e.…”

Section: Introductionmentioning

confidence: 99%

Multi-time-lag PIV analysis of steady and pulsatile flows in a sidewall aneurysm

et al. 2014

View full text Add to dashboard Cite

The effect of inflow waveform on the hemodynamics of a real-size idealized sidewall intracranial aneurysm (IA) model was investigated using particle imaging velocimetry (PIV). For this purpose, we implemented an error analysis based on several PIV measurements with different time lags to ensure high precision of velocity fields measured in both the IA and the parent artery. The relative error measured in the main part of the circulating volume was \1 % despite the three orders of magnitude difference of parent artery and IA dome velocities. Moreover, important features involved in IA evolution were potentially emphasized from the qualitative and quantitative flow pattern comparison resulting from steady and unsteady inflows. In particular, the flow transfer in IA and the vortical structure were significantly modified when increasing the number of harmonics for a typical physiological flow, in comparison with quasi-steady conditions.

show abstract

“…A condition to assess the flow features by experimental investigations based on the PIV method is having the capability to accurately measure the velocities close to the walls. Despite numerous recent experiments, the assessment of the near wall velocity field is still a challenge for researchers working on this subject [3].a a PIV is an optical non-intrusive velocity measurement method that could be briefly described as follows. A plane in the flow field seeded with light scatter particles has to be illuminated with two successive laser pulses delayed by a time ∆t.…”

Section: Introductionmentioning

confidence: 99%

On investigating the flow through an axisymmetric channel with sudden changes in geometry

Giurgea

Bode

Nascutiu

et al. 2013

EPJ Web of Conferences

View full text Add to dashboard Cite

Abstract. The paper presents the authors first experience in the complementary use of the CFD and PIV methods for the investigation of a steady flow of an incompressible fluid through a successive sudden contraction (diameters ratio 4:1) and expansion (diameters ratio 1:2). The investigation of this flow was chosen by the authors as a test case for an assessment of the capability of a standard PIV system to make accurate measurements of the 2D velocity field. With this aim in view, in a first step of the study the flow was investigated by numerical simulations using the CFD code FLUENT, in order to map the velocity field and to identify the zones covered by recirculation flow. An experimental set-up was built and PIV investigations were conducted for validating the numerical simulation results. It was observed that there currently exist important technical limitations of the experimental setup in assessing the velocities close to the walls, and implicitly affecting the possibility of validating the results of the numerical simulation. That is why, based on the PIV investigation, at the current stage of the study the authors can only advance qualitative observations and identify possible solutions to upgrade the PIV setup.

show abstract

Unsteady velocity measurements in a realistic intracranial aneurysm model

Cited by 23 publications

References 22 publications

Emerging fractal patterns in a real 3D cerebral aneurysm

Emerging fractal patterns in a real 3D cerebral aneurysm

Multi-time-lag PIV analysis of steady and pulsatile flows in a sidewall aneurysm

On investigating the flow through an axisymmetric channel with sudden changes in geometry

Contact Info

Product

Resources

About