Simulation of Hemodynamics in Cerebral Aneurysms Using Non-Newtonian and Newtonian Models

Intracranial aneurysms are pathological dilations of cerebral arteries that may remain clinically silent for years but can rupture catastrophically, leading to aneurysmal subarachnoid hemorrhage with high mortality and long-term neurological disability. Computational fluid dynamics has become an essential tool for quantifying patient- or geometry-specific hemodynamic conditions, including wall shear stress, oscillatory shear index, and residence-time-related measures, which are associated with aneurysm initiation, growth, and rupture. This study investigates the influence of blood rheology modeling on predicted hemodynamics in cerebral aneurysms. Flow is simulated in two aneurysm geometries using a finite element solver, comparing a constant-viscosity Newtonian model against two widely used shear-thinning formulations, namely the Cross and Carreau models. To ensure numerical robustness, a systematic mesh-independence study is performed using progressively refined discretizations. The aim is to clarify the role of rheological assumptions in computational hemodynamic analysis and to provide guidance for selecting appropriate viscosity models in cerebral aneurysm simulations.