Abstract

The study presents a mesh dependency study for a carotid artery bifurcation geometry of a real-life specimen. The results of time-averaged velocity profiles at artery control surfaces and wall shear stresses are compared between a set of structured and unstructured meshes, with varying non–dimensional boundary layer first element thickness (y+) parameter. A set of four meshes in total is considered: a full–hexagonal structured mesh, an unstructured tetrahedral mesh with prism inflation layer, both created for y+=1 and y+=30. Apart from numerical results, overall mesh creation work time, overall analysisstability are compared with the mesh quality results: cell non–orthogonality, cell skew and aspect ratio. Numerical results are validated against results of real–life CT examination performed in Poznań Medical University.

Highlights

  • Application of numerical methods in the field of biomechanics of flows allows distinguishing the mechanical reasons for the occurrence of some pathological changes such as progressive stenosis

  • Numerical results are validated by comparing the velocity profiles at control point in function of time with results of Doppler USG at internal carotid artery (ICA) and external carotid artery (ECA), 30 mm from the bulb

  • A metric used to compare the velocity profiles is a modification of standard deviation of discrete random variable, where the mean value of the measured velocity at given outlet is replaced velocity measured at given time

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Summary

Introduction

Application of numerical methods in the field of biomechanics of flows allows distinguishing the mechanical reasons for the occurrence of some pathological changes such as progressive stenosis. Physical quantities used to describe the phenomena occurring in fluid dynamics can be considered in medical aspects to describe the causes of some specific group of vascular diseases, such as atherosclerosis or cerebral aneurysm [1, 2]. When numerical modelling this type of flow, the key aspect in the detection of boundary layer detachment is the turbulence model and the quality of the mesh: especially its resolution and non-dimensional boundary layer first element thickness (y+) parameter. Validation of numerical calculations with results from Doppler examination allows for assessing the accuracy of calculations

Problem description
Geometry description
Solvers and setup
Validation
WSS analysis
Velocity distribution
Summary
Conclusions
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