Influence of Symmetric Multi‐Overlapping Stenosis on Carreau Blood Rheology: A 3D Computational Study

ABSTRACT

Arterial conduits with more than two consecutive constrictions are classified as exhibiting multiple overlapped stenoses, a pathological morphology with critical implications for vascular health. Accurate comprehension of the associated hemodynamic behavior necessitates advanced geometric modeling and mathematical analysis. In this study, blood is idealized as a non‐Newtonian Carreau fluid to effectively capture its shear‐dependent viscosity characteristics. The stenotic model comprises two overlapping constrictions, yielding three peak and two trough locations, where velocity, wall shear stress (WSS), and temperature distributions are analyzed in detail constituting a key novelty of this work. A mathematical formulation is developed and solved using the Finite Element Method (FEM) to retrieve numerical approximations of the governing equations. Results reveal a marked acceleration of blood flow within the stenotic zones and a pre‐stenotic rise in WSS. Moreover, the temporal increase in the Nusselt number indicates a concurrent enrichment in heat transmission efficiency. It is noticed that the velocity is increasing with increment in the stenosis's height which increases the shear rate. Due to increase in shear rate, WSS also enhances and damages the vessel wall. The interaction between adjacent stenotic regions enhances flow disturbances, resulting in stronger velocity gradients and possible flow separation downstream of each constriction. These findings deliver critical insight into the physiological consequences of multi‐segmented stenotic geometries, including heightened risk for ischemic conditions and thrombotic events. The developed model provides a rigorous quantitative framework for evaluating pathological blood flow dynamics and optimizing treatment planning in cardiovascular medicine.