Pulsatile flow in cerebral aneurysms
We develop a computational method for the simulation of the flow of
blood through cerebral aneurysms, which may occur in the human
brain. These aneurysms are weak regions in the vessel, presenting a
serious risk of rupture to the patient. The goal is to understand
the flow in these diseased parts of the vessel system. An immersed
boundary method, based on volume penalization, is developed to
compute the pulsatile flow. The raw medical imagery representing
the patient-specific geometry is processed to extract the
‘masking function’, which is needed to simulate flow patterns
and obtain wall shear stresses under realistic physiological
conditions. We illustrate the numerical method for several model
and realistic aneurysms. In each case we observe a transition to
complex time-dependent flow in case the flow speed and/or the
aneurysm size become sufficiently large. High frequency variations
appear in the flow, which may be an easy method for monitoring the
progress of a developing aneurysm and the risk it represents.
