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Prediction of vortex structures in pulsatile flow through S-bend arterial geometry with different stenosis levels

Khan Piru Mohan, Raj Apurva, Alam Md. Irshad, Chakraborty Suman, Roy Somnath

Biocybernetics and Biomedical Engineering

2023

Vol. 43, no. 1

298--312

Arterial stenosis poses a high cardiovascular risk, and clinical intervention is needed when these stenoses grow beyond a specific limit. The study of vortex dynamics in these diseased arteries can be beneficial to understand its severity. Therefore, in the present work, we have investigated the flow structures in an S-bend arterial geometry with different levels of stenosis using a sharp interface immersed boundary method. We have observed an onset of Kelvin-Helmholtz-type vortex roll-up for higher degrees of stenoses. Fluctuations in the wall shear stress are observed for higher stenosis degrees. However, these fluctuations depend on the position and length of the stenosis. Newtonian and non-Newtonian Carreau fluids predict similar vortex structures, although minor differences in the Kelvin-Helmholtz vortex structures and associated fluctuations are observed in the diastolic phase. The Newtonian fluid predicts a slightly longer low time-averaged wall shear stress (≤0.5 Pa) region immediately after the stenosis compared with the Carreau fluid in the 58 % blockage S-bend artery.

Simulation of steady laminar blood flow through arterial stenosis using computational fluid dynamics

Banerjee M. K., Ganguly R., Datta A.

International Journal of Applied Mechanics and Engineering

2009

Vol. 14, no 1

91-111

The flow of blood through a rigid artery with different degrees of stenosis has been studied. Two different shapes (rectangular and cosine) of stenosis are considered while blood is modeled either as a Newtonian or non-Newtonian fluid. Three different degrees of stenosis, expressed in percentage, are considered representing mild to severe stenoses. The flow separates from the arterial wall at the stenosis and reattaches at a point downstream, forming a recirculating eddy. The pressure drop over the length of the artery varies for the different cases indicating the impact on the heart. A peak in the wall shear stress is observed at the location of the stenosis and zero stress points are observed where the flow separates and reattaches the wall. Results show marked differences in the flow pattern and shear stress between Newtonian and non-Newtonian models. Moreover, the power-law model exhibits a different trend as compared to the Casson model in predicting the flow field and wall shear stress.