High‐order algorithms for vascular flow modelling

Peiró, Joaquim; Giordana, Sergio; Griffith, Cody; Sherwin, Spencer J.

doi:10.1002/fld.270

Cited by 21 publications

(7 citation statements)

References 19 publications

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“…A hybrid mesh of body-conforming prismatic and unstructured tetrahedral elements was created using non-proprietary software [18,19]. The prismatic boundary layer mesh generated at the walls had thickness 0.3D.…”

Section: Methodsmentioning

confidence: 99%

Effect of reverse flow on the pattern of wall shear stress near arterial branches

Kazakidi

Plata

Sherwin

et al. 2011

J. R. Soc. Interface.

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Atherosclerotic lesions have a patchy distribution within arteries that suggests a controlling influence of haemodynamic stresses on their development. The distribution near aortic branches varies with age and species, perhaps reflecting differences in these stresses. Our previous work, which assumed steady flow, revealed a dependence of wall shear stress (WSS) patterns on Reynolds number and side-branch flow rate. Here, we examine effects of pulsatile flow. Flow and WSS patterns were computed by applying high-order unstructured spectral/ hp element methods to the Newtonian incompressible Navier -Stokes equations in a geometrically simplified model of an aorto-intercostal junction. The effect of pulsatile but non-reversing side-branch flow was small; the aortic WSS pattern resembled that obtained under steady flow conditions, with high WSS upstream and downstream of the branch. When flow in the side branch or in the aortic near-wall region reversed during part of the cycle, significantly different instantaneous patterns were generated, with low WSS appearing upstream and downstream. Time-averaged WSS was similar to the steady flow case, reflecting the short duration of these events, but patterns of the oscillatory shear index for reversing aortic near-wall flow were profoundly altered. Effects of reverse flow may help explain the different distributions of lesions.

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Section: Methodsmentioning

confidence: 99%

Effect of reverse flow on the pattern of wall shear stress near arterial branches

Kazakidi

Plata

Sherwin

et al. 2011

J. R. Soc. Interface.

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“…We then proceed to interpolate a closed B-spline for each section using a least-squares approach. This is described in detail in Reference [5]. This enables us to accurately generate a finite set of points on the interpolated curve and on an interior curve offset along the normal.…”

Section: Image Segmentation and Point Selectionmentioning

confidence: 98%

“…Here we adopt the implicit function approach previously described in Reference [5] where the ideas presented in References [4,6] were adapted and applied to the reconstruction of a parametric spline representation of the surface. The main reason for the use of an implicit function is its ability of smoothly interpolating sections of complicated geometry, and even changing topology, without the need of user-defined parameters.…”

Section: Introductionmentioning

confidence: 99%

Shape reconstruction from medical images and quality mesh generation via implicit surfaces

Peiró

Formaggia

Gazzola

et al. 2006

Numerical Methods in Fluids

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SUMMARYThe ability of automatically reconstructing physiological shapes, of generating computational meshes, and of calculating flow solutions from medical images is enabling the introduction of computational fluid dynamics (CFD) techniques as an additional tool to aid clinical practice.This article presents a set of procedures for the shape reconstruction and triangulation of geometries derived from a set of medical images representing planar cross sections of the object. The reconstruction of the shape of the boundary is based on the interpolation of an implicit function through a set of points obtained from the segmentation of the images. This approach is favoured for its ability of smoothly interpolating between sections of different topology. The boundary of the object is an iso-surface of the implicit function that is approximated by a triangulation extracted by the method of marching cubes. The quality of this triangulation is often neither suitable for mesh generation nor for flow solution. We discuss the use of mesh enhancement techniques to maximize the quality of the triangulation together with curvature adaption to optimize mesh resolution.The proposed methodology is applied to the reconstruction and discretization of two physiological geometries: a femoral by-pass graft and a nasal cavity.

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“…Smooth implicit functions for 3D reconstruction have been associated with spectral/hp high order elements for blood flow computations [36]. Bicubic spline patches, which are interactively defined and projected onto the implicit surface, serve as the initial element for meshing [37].…”

Section: Image-based Computational Modelmentioning

confidence: 99%

Biofluid Flow and Heat Transfer

Thiriet¹,

Sheu²,

Garon³

2016

Handbook of Fluid Dynamics, Second Edition

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2nd EditionInternational audienceMajor moving biological fluids, or biofluids, are blood and air that cooperate to bring oxygento the body’s cells and eliminate carbon dioxide produced by these cells. Blood is conveyed ina closed network composed of 2 circuits in series — the systemic and pulmonary circulation—, each constituted by arteries, capillaries, and veins, under the synchronized action of theleft and right cardiac pumps, respectively. Air is successively inhaled from and exhaled to theatmosphere through the airway openings (nose and/or mouth). In the head, blood generatesthe cerebrospinal fluid in choroid plexi of all compartments of the ventricular system andreceives it in arachnoid villi. Other biofluids are either secreted, such as bile from the liverand breast milk that both transport released substances with specific tasks, or excreted,such as urine from kidneys or sweat from skin glands that both convey useless materials andwaste produced by the cell metabolism. In addition to the convective transport, peristalsis,which results from the radial contraction and relaxation of mural smooth muscles, propelsthe content of the lumen of the muscular bioconduit (e.g., digestive tract) in an anterogradedirection.Blood circulation and air flow in the respiratory tract are widely explored because oftheir vital functions. Note that inhaled air is transported through the respiratory tract bytwo processes: convection down to bronchioles and diffusion down to pulmonary alveoli.1Furthermore, investigations of these physiological flows in deformable bioconduits give riseto models such as the Starling resistance that themselves become object of new study fieldsin physics and mechanics (e.g., collapsible tubes) as well as of new developments in math-ematical modeling and scientific computing. Whereas fluid–structure interaction problemsin aeronautics and civil engineering deal with materials of distinct properties, blood streamand vessel wall correspond to two domains of nearly equal physical properties, as both bloodand vessels have densities close to that of water. New processing strategies must then beconceived

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High‐order algorithms for vascular flow modelling

Cited by 21 publications

References 19 publications

Effect of reverse flow on the pattern of wall shear stress near arterial branches

Effect of reverse flow on the pattern of wall shear stress near arterial branches

Shape reconstruction from medical images and quality mesh generation via implicit surfaces

Biofluid Flow and Heat Transfer

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