AuthorsK. Valen-Sendstad, K. Mardal, M. Mortensen, B. A. P. Reif and H. P. Langtangen
TitleDirect Numerical Simulation of Transitional Flow in a Patient-Specific Intracranial Aneurysm
AfilliationScientific Computing, , Scientific Computing
Project(s)Center for Biomedical Computing (SFF)
Publication TypeJournal Article
Year of Publication2011
JournalJournal of Biomechanics

In experiments turbulence has previously been shown to occur in intracranial aneurysms, but the turbulent effects on the arterial wall have not been investigated. The effects of turbulence induced oscillatory wall stresses could be of great importance in understanding aneurysm rupture due to the local arterial wall response to such hemodynamical forces. To investigate the effects of turbulence on blood flow in an intracranial aneurysm, we performed a high resolution computational fluid dynamics (CFD) simulations in a patient specific middle cerebral artery (MCA) aneurysm using a realistic, pulsatile inflow velocity. The flow showed transition to turbulence just after peak systole, and the turbulent fluctuations increased in intensity until mid deceleration, before relaminarization occurred during diastole. The flow impinged with an angle nearly normal onto the aneurysm dome, and the turbulence structures greatly affected both the frequency of change of wall shear stress (WSS) direction and WSS magnitude, which reached a maximum value of 41.5 Pa. The recorded frequencies were predominantly in the range of 1-500 Hz. The current study confirms, through properly resolved CFD simulations, that turbulence can occur in intracranial aneurysms. Because of the local arterial wall response to hemodynamical forces, the effects of oscillatory WSS caused by turbulence, could be correlated with aneurysm rupture, and should be investigated experimentally. Keywords: Computational fluid dynamics, Blood flow, Direct Numerical Simulation, Turbulence, Middle cerebral artery aneurysm

Citation KeySimula.simula.636