Abstract
The application of computational fluid dynamics (CFD) in medicine is attracting growing attention, as patient-specific numerical models can help optimize clinical management.
CFD can be used to simulate blood flow in diseased human vessels, such as brain aneurysms.
Previous studies on patient-specific blood flow models have almost exclusively prescribed the no-slip boundary condition (BC) on walls. Although easy to implement, its validity at the interface between blood and the vessel wall is questionable. The novelty of our approach is prescribing a more general BC called Navier slip BC, which presumes a linear proportionality between the tangential part of the velocity on the wall and the shear stress using an additional parameter. We used a patient-specific aneurysm geometry and assumed that the vessel wall was impermeable, which is implemented using the Nitsche method. Blood flow is governed by generalized incompressible Navier-Stokes equations; thus, both Newtonian and non-Newtonian models were considered. We used the FEniCS module with a nonlinear solver adopted from the PETSc library to compute the velocity and pressure fields. From these quantities, we compute the wall shear stress (WSS), the oscillatory shear index, and the oscillatory velocity index. We show two numerical methods for computing WSS and evaluate differences in hemodynamics using different models and slip parameters.