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Analysis of coupled problem between collapsible tube and pulsatile flow by means of computational mechanics

溃缩管与脉动流耦合问题的计算力学分析

基本信息

批准号：
11680855
负责人：
BANDO Kiyoshi
金额：
$ 2.43万
依托单位：
Kansai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680855/
关键词：
Computational Mechnics Numerical Simulation Biomechanics Coupled Problem Blood Flow Tube Law Collapsible Tube Pulsatile Flow 有限要素法

项目摘要

The coupled problem between collapsible tube and flow in it was solved by means of computational mechanics to researeh fluid-dynamic cause of blood disease such as arteriosclerosis. The collapsible tube is a model of blood vessels. When the tube law is used, the coupled problem is formulated as one-dimensional problem in the axial-direction of the tube. The pulsatile flow in a blood vessel is modeled as an isolated pressure wave propagating in the collapsible tube by using the tube law. The calculated pressure waves agreed well with experimental results. A two-dimensional calculation method is proposed to obtain the tube law with high accuracy and a three-dinensional FEM calculation of largely deformed tube by buckhng was performed to check three-dimensional effects of the tube on the tube law. A three-dimensional pulsatile flow calculation in a tapered U-bend as a model of an aortic arch was performed by means of FEM. The wall was asswned to be rigid due to the fact that the aortic arch has high rigidity. The obtained velocity profiles in the cross-sections are compared to experinental results, and secondary flow in the cross-section is shown. A method for calculating pressure distribution in the axial-direction pf the collapsible tube which is deformed largely by buckling due to low pressure in the tube was proposed. The three-dimensional flow in the largely deformed tube was numerically simulated. The axial velocity profiles in cross-sections obtained in the calculation were compared with experinental results, and reasonable agreement between them was obtained. The secondary flow distribution in the cross-sections, shear rate distribution in the tube and wall shear stress distribution are calculated. It is shown that high wall shear stress region occurs around the center of the cross'section which is buckled in figure-8 shaped.

为了研究动脉硬化等血液疾病的流体动力学原因，用计算力学方法解决了可折叠管与管内流动的耦合问题。可折叠管是血管的模型。当采用圆管法时，耦合问题在圆管轴向可化为一维问题。利用圆管定律，将血管中的脉动流模型化为孤立的压力波在可折叠管内传播。计算的压力波与实验结果吻合较好。为了获得高精度的圆管定律，提出了一种二维计算方法，并对大变形圆管进行了三维有限元计算，以检验圆管的三维效应对圆管定律的影响。本文用有限元法对主动脉弓锥形U形弯管内的三维脉动流进行了计算。由于主动脉弓具有高刚度，因此壁被认为是刚性的。将计算得到的横截面速度分布与实验结果进行了比较，并显示了横截面中的二次流。本文提出了一种计算可伸缩管由于管内压力低而产生较大屈曲变形时轴向压力分布的方法。对大变形管内的三维流动进行了数值模拟。将计算得到的截面轴向速度分布与实验结果进行了比较，两者吻合较好。计算了截面上的二次流分布、管内剪切速率分布和壁面剪应力分布。结果表明，高壁面剪应力区出现在屈曲成“8”字形截面的中心附近。