Direct numerical simulation of a pulsatile flow in a stenotic channel using immersed boundary method
Direct numerical simulation of a pulsatile flow in a stenotic channel using immersed boundary method
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DOI：
10.1002/eng2.12444
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发表时间：
2021-08-05
影响因子：
2
通讯作者：
Park, Jae Sung
中科院分区：
文献类型：
--
作者：
Mirfendereski, Siamak;Park, Jae Sung
建立了一种三维直接数值模拟模型，结合浸入边界法模拟了具有单侧和双侧半圆收缩的平面通道内的脉动流动。为了与大动脉血流相关，在750和1000雷诺数下进行了模拟。给出了基于流动物理和合成壁面剪切应力（WSS）的血流动力学参数。对瞬时涡动力学、平均流动特性和湍流能谱进行了流动物理评价。随后，在狭窄壁上计算三个基于WSS的参数，即时间平均WSS、振荡剪切指数和相对停留时间，并与血流物理相关联，以确定动脉粥样硬化斑块进展的易感区域。结果表明，双狭窄通道导致下游高强度和宽带湍流特征，提高了后狭窄区域wss参数的临界值。此外，两条狭窄血管之间的间隙区域显示多重强再循环，使该区域极易发生动脉粥样硬化进展。研究了窄度对基于wss的参数的影响高达60%。随着遮挡程度的增加，更大的区域涉及到基于wss的参数的非生理范围。
A three-dimensional direct numerical simulation model coupled with the immersed boundary method has been developed to simulate a pulsatile flow in a planar channel with single and double one-sided semicircular constrictions. For relevance to blood flow in large arteries, simulations have been performed at Reynolds numbers of 750 and 1000. Flow physics and resultant wall shear stress (WSS)-based hemodynamic parameters are presented. The instantaneous vortex dynamics, mean flow characteristics, and turbulent energy spectra are evaluated for flow physics. Subsequently, three WSS-based parameters, namely the time-averaged WSS, oscillatory shear index, and relative residence time, are calculated over the stenotic wall and correlated with flow physics to identify the regions prone to atherosclerotic plaque progression. Results show that the double stenotic channel leads to high-intensity and broadband turbulent characteristics downstream, promoting critical values of the WSS-based parameters in the post-stenotic areas. In addition, the inter-space area between two stenoses displays multiple strong recirculations, making this area highly prone to atherosclerosis progression. The effect of stenosis degree on the WSS-based parameters is studied up to 60% degree. As the degree of occlusion is increased, larger regions are involved with the nonphysiological ranges of the WSS-based parameters.