Lattice Boltzmann model for simulation of flow in intracranial aneurysms considering non-Newtonian effects

We propose a robust modified central Hermite polynomial-based multiple relaxation time lattice Boltzmann model with independent control over relaxation of acoustic modes for non-Newtonian fluids, more specifically in the context of blood flow in intracranial aneurysms. The use of the robust collision operator along with the implicit computation of the non-linear stress allows for a very wide operation domain in terms of time step and grid-size. The solver is first validated via well-documented configurations such as the 2D Poiseuille-Hagen and lid-driven cavity flows with a power-law fluid. The results clearly show second-order convergence of the scheme. The model is then used to simulate pulsating flow in an ideal aneurysm geometry with four different viscosity laws, namely, Newtonian, power-law, Carreau-Yasuda, and Cross. The results show that the assumption of high shear rates does not necessarily hold within the aneurysm sac. Finally, the solver is used to simulate pulsating blood flow in a patient-specific configuration.