Numerical analysis of hemodynamic parameters in stenosed arteries under pulsatile flow conditions

Abstract

This research studies the changes in flow patterns and hemodynamic parameters of diverse shapes and sizes of stenosis. Six different shapes and sizes of stenosis are constructed to investigate the variations in hemodynamics as the morphology changes. Changes in shape (trapezoidal and bell-shaped) and sizes of stenosis change the stresses on the walls and their flow patterns. TAWSS and OSI results specify that trapezoidal stenosis exerts greater stress than bell-shaped stenosis. Also, as the length of the trapezoidal stenosis increases, the TAWSS increases, whereas the trend is the opposite for bell-shaped stenosis. Later, this paper also studies different degrees of stenosis extracted from real images. Changes in velocity flow patterns, wall shear stress (WSS), Time-averaged wall shear stress (TAWSS) and Oscillatory shear index (OSI) have been studied for these images. Results illustrate that the peak velocity rises drastically as the stenosis percentage increases. Negative velocity is seen close to the artery's walls, indicating flow separation. This flow separation region is seen throughout the cycle except in the accelerating flow region. An increase in stenosis also increases WSS and TAWSS drastically. Negative WSS is seen downstream of stenosis, indicating flow recirculation. Such negative WSS in the blood vessels also promotes endothelial dysfunction. OSI values greater than 0.2 are seen near the stenosis region, indicating atherosclerosis growth. Regions of high OSI and low TAWSS are also identified, indicating probable regions of plaque development.

Keywords

• Cardiovascular
• Stenosis morphology
• Real geometry
• CFD simulation
• Artificial compressibility method
• HLLC-AC