Effects of Stenosis Severity and Reynolds Number on Viscoelastic Oldroyd-B Blood Flow in a Stenosed Artery

Arterial stenosis significantly alters blood-flow velocity, flow separation, and wall stress distribution by reducing the vessel cross-sectional area. In this study, blood flow was modeled as a viscoelastic fluid using the Oldroyd-B model in a two-dimensional rigid artery with a cosine-shaped stenosis. The analysis extended previous work by considering four stenosis severities (۲۵%, ۳۵%, ۴۵%, and ۵۵%) and Reynolds numbers ranging from ۱ to ۳۰۰ at a constant Weissenberg number of ۰.۱. Simulations were performed in COMSOL Multiphysics ۶.۲ using the finite element method, and validation showed a maximum discrepancy below ۲%. The results demonstrated that increasing stenosis severity increases the maximum velocity and produces a flatter core velocity profile at higher Reynolds numbers. For ۲۵% stenosis, flow recirculation appeared at approximately Re = ۵۰ and expanded downstream as the Reynolds number increased. Increasing stenosis severity also markedly intensified flow separation. Moreover, viscoelastic extra stress was concentrated near the stenosis throat, with greater stenosis severity producing higher stress peaks. Overall, both stenosis severity and flow inertia are critical parameters for predicting flow separation and stress concentration in stenosed arteries.

کلیدواژه ها:

Oldroyd-B model ، Viscoelastic blood flow ، Arterial stenosis ، Reynolds number ، Flow separation.